Learn step by step how to make a smoked flank steak on ANY grill or smoker! Whether you’ve got a Traeger or Pit boss pellet grill, Weber kettle, or even a propane gas grill, we’ve got you covered.
Take your flank steak, sometimes known as carne asada, to the next level by marinating, smoking, and REVERSE SEARING to perfection before resting and serving!
Let’s get started!
A flank steak, sometimes called a skirt steak or also known as a london broil when cut a little thicker, is not a particularly revered cut of beef in the fancy pants world of steaks.
Like other second class steak cuts like the hangar steak, it’s kind of lean, kind of tough, and not usually in the center of your butcher’s display case alongside the prized ribeyes and filet mignons.
But when cooked and prepared just right, typically marinated and grilled hot and fast, flank steak can be one of the most delicious cuts of beef you will ever try.
And today we are going to take it up another notch by SMOKING our flank steak before we reverse sear it to perfection.
We are going to cover:
- How to prepare your flank steak for the smoker with a good marinade and rub
- The best wood choices for a smoked flank steak
- How to set up different grills and smokers for a smoked flank steak
- What temperature to smoke your flank steak
- How to reverse sear your smoked flank steak for the most delicious flavor and texture.
- How to know precisely when your smoked flank steak is finished
- How to rest, slice, and serve your perfectly smoked and reverse seared flank steak
Wow, that’s a lot…so let’s jump in!
What is a Flank Steak?
Flank steak actually comes from the Top Round section, which is found on the steer’s lower hind quarters, or “flank”, hence the terminology.
“London Broil” and “Skirt Steak” are simply marketing terms likely developed by some butchers many years ago trying to sell some of their lesser desired cuts of beef to the wine and cheese crowd.
But they all basically mean the same thing.
Cuts labeled as London broil tend to be a little thicker than those labeled as flank steak, and skirt steaks tend to be longer and thinner, but most of the time you will find them all in the 1.5 – 3 lb range.
A 2 lb flank steak is perfect for our purposes today.
How to Prepare a Flank Steak for the Smoker
A flank steak is generally marinated overnight to help break down some of the lean connective tissue.
Unlike beef brisket or ribs, which have lots of fatty connective tissue that we can break down with low and slow cooking, with a flank steak we would just end up drying out the meat due to lack of fat content by the time any connective tissue broke down.
Therefore, our strategy is to to marinate, smoke briefly just for smokey flavor, and then cook it hot and fast to finish.
Trim the Fat and Silverskin
Take a look at your flank steak and see if any fatty pieces need to be removed from the edges.
This can also square off your smoked flank steak and give it a little nicer presentation if you care about that sort of thing.
Next you’ll want to use a good knife, like our favorite boning knife from iMarku, and trim off the silverskin along the broad surfaces of the top and bottom of the flank steak.
Silverskin can end up a little chewy and unappetizing if not removed, similar to the membrane we always remove from the back of a slab of baby back ribs.
Top Seasonings and Marinades for Smoked Flank Steak
Because flank steak is so naturally lean and tough, along with being relatively thin, it benefits from a good marinade before cooking to keep it from drying out on the grill or smoker.
Generally this is done with a combination of oil and acid, which can come from citrus, vinegar, or both.
For our smoked london broil we opted for a traditional red wine vinegar based marinade, but in the recipe at the bottom for our smoked flank steak we are going to opt for a combination of Worcestershire, garlic, and soy sauce for a more savory and umami flavor.
You can also simply season you smoked flank steak with salt and pepper, or use your favorite BBQ rub.
If you are going for more traditional steak flavors, or don’t have the time to make your own homemade marinade from scratch, you can use 2 parts oil to 1 part red or white wine vinegar along with something like a Montreal Steak Seasoning rubbed on the flank steak.
However, if you plan to reverse sear like we recommend, stay away from sugary rubs that will burn with high direct heat.
We like Bad Byron’s Butt Rub for reverse seared beef when we are avoiding sugar as you get great BBQ flavor without having to worry about the rub burning.
Whisk the marinade ingredients together and pour over the flank steak in a wide and shallow baking dish or put everything in a gallon size storage bag and put it all in the refrigerator for at least 4-6 hours, preferably overnight.
Salt and Marinate Overnight
When you are preparing your smoked flank steak its best to season and marinate it at least 4-6 hours before smoking, preferably overnight, before putting it on the smoker or grill.
Pay attention to your salt level. If you are using very salty marinade ingredients like soy sauce you probably don’t need to also rub salt all over the meat too.
However, if you are just using olive oil and red wine vinegar, make sure to salt the meat first.
Either way allows the rub and marinade time to penetrate the meat, ensuring you have flavorful steak all the way to the center and not just salty on the exterior, and bland in the middle.
Also, did you know that if the meat is fully salted throughout, it is chemically better able to hold onto is juices and retain more moisture during the cooking process?
This is why the boiling point of saltwater is higher than that of pure water.
Pro Tip: Don’t use aluminum baking pans or foil trays when working with vinegar marinades as the acid can interact with the metal and leave a sour taste on the meat. Stick with plastic or glass!
Best Wood Choices for Smoked Flank Steak
For a big robust piece of beef like a smoked flank steak, we’d recommend going with something like hickory or pecan that will stand out and also compliment the beef well.
If you want to keep it simple and straightforward, choose a lighter smoking wood like oak, apple, or peach, although these lighter fruitwoods may not impart as much smokey flavor into the beef as they will with chicken or fish.
When in doubt, you can always mix and match your choices!
Best Times and Temperatures for Smoking a Flank Steak
You will need to watch both your cooking temperature and internal temperature carefully when smoking the flank steak.
We recommend setting up the grill or smoker for indirect heat to cook at 200°F.
We will crank the temperature later to really sear and cook the flank steak, but during the smoking phase, we don’t want to overcook and dry out the flank steak, just add smoky flavor.
Target Internal Temperature for Smoked Flank Steak
You HAVE to use a good instant read meat thermometer to know where the internal temperature is of your smoked flank steak.
Remember there is not much fat on this cut of beef so if you overcook it even by a little bit it will dry out FAST!
If your smoked flank steak is thick enough, you’ll want a good leave in probe thermometer like the Thermopro as well as a second instant read thermometer to spot check as you get close to pulling it off the smoker.
While we have used and recommended ThermoPro for years, lately we have also become big fans of the MEATER leave in thermometer.
It is extremely accurate and has an incredible 165 foot bluetooth range and works right with your smartphone so you don’t need to carry a separate controller around with you like many other remote thermometers require.
It’s got a great free app that is constantly being updated and even has an algorithm to predict how much longer your type of meat will take to cook based on cooking temperature, target temperature, current internal temperature.
It’s like a GPS for your meat!
Anyways, back to our smoked flank steak…
We are going to slowly bring the internal temperature up to about 110°F, then crank the heat as hot as we can to reverse sear the flank steak on each side for about 2-3 minutes. Once the steak reaches 130°F internally we remove it from the heat.
“But wait a minute, I usually pull my filets and ribeyes off at 120-125°F!”
Believe it or not, tougher steaks like flank steak taste better when cooked to medium vs. medium rare.
This is because they can remain unpleasantly chewy if not cooked up to the proper temperature.
You will notice most flank steak, or carne asada cooked for tacos and fajitas, is cooked to at least medium or even medium well so that it is not too chewy or unappetizing when bitten into.
By marinating, letting the meat rest, and slicing it against the grain, it will still be very tender and juicy, (without tasting chewy and underdone) even if you cook it to medium-well.
How Long Does it Take to Smoke a Flank Steak?
Most store bought flank steaks will be in the 1.5 – 2 lb range and will take about 30-45 minutes to absorb some good smokey flavor INDIRECTLY at 200°F, then only about 2-3 minutes per side over hot DIRECT heat to sear and finish cooking.
Remember to use that instant read thermometer often.
It’s about temperature, not time! We are trying to add some smokey flavor while we SLOWLY bring the smaoked flank steak up to 110°F internally.
A monster 3-4 lb flank steak, especially right out of the refrigerator may take an hour to hit 110°F internally.
On the other hand, a small room temperature steak running on a hot smoker on a humid day may only take 20 minutes to get there.
Reverse Sear Method
“Reverse Searing” is just a fancy term for DIRECT searing your meat at the very end in order to get a nice crispy exterior crust that you just can’t get from low and slow INDIRECT smoking alone.
This also works great for cuts of meat like flank steak that need time to absorb smokey flavor but then benefit from a hot and fast sear rather than low and slow cooking.
With larger cuts of meat like hams and pork butts, they will develop a nice exterior crust naturally just due to the long length of time they spend in the smoker, and the sugary rubs that are typically used in their preparation.
Much like our smoked ribeye steaks and smoked red wine infused london broil, we like to smoke and then reverse sear our flank steak, simply by moving it over to the hot part of the grill or finishing it in a hot cast iron pan, griddle, or even inside under the oven broiler.
If you are using a pellet grill that doesn’t have a direct heat option, and finding it hard to get that high direct heat for searing, try laying a couple of Grill Grates over a section of the grill.
These work great for creating a hot searing station on a pellet grill using the ambient heat the pellet grill is already creating.
See the pellet grill section below for more details.
In order to reverse sear a flank steak without overcooking it, only bring your internal temperature up to about 110°F on an internal meat thermometer. Then immediately sear it hot and fast for about 2-3 minutes on each side.
Then check your temperature again and place the meat back in the smoker or on the indirect side of the grill until the internal temperature hits 130°F.
No Reverse Sear
Sometimes, like with the smoked rack of lamb, we can go either way on whether to bother with the reverse sear.
Sometimes just smoking the meat up to the right temperature works well enough by itself.
Not so much with steaks.
You really need to reverse sear them.
It doesn’t matter which method you choose, but just smoking the flank steak low and slow until it’s finished is not an ideal way to cook it.
You won’t ever get that sizzling exterior crust or beautiful brown coloring from the maillard reaction that takes place at high heat.
Your thicker striations of fat will never render and the meat will remain an unappetizing gray color.
So take the extra 5 minutes, whether it’s over a hot grill burner, over some charcoal, or right under the broiler in the oven, and sear that smoked flank steak to finish it off.
You’ll be glad you did!
Setting up your Smoker for a Smoked Flank Steak
Vertical or Offset Charcoal Smoker
Fill your firebox or lower charcoal basin with about 1/4 a bag of unlit charcoal and create a small hollowed out depression in the center where you can add your lit briquets.
If your smoker comes with a water pan, like the Weber Smokey Mountain, fill the water pan as well to help stabilize the temperature and add moisture to the cooking chamber.
Light a charcoal chimney about 1/4 way with charcoal and wait about 20 minutes for it to fully ignite. You don’t want TOO many lit briquests initially or the temperature will get too high too fast and be unmanageable.
Fill your water pan first, then add the lit briquets to the center depression you created.
Keep the dampers about 1/2 way to 3/4 open until the temperature is to about 180°F. Then slowly close them down until you are maintaining a temperature of 200-225°F.
This will obviously take longer on a cold winter day than a hot summer one.
Add 1-2 chunks of smoking wood once the smoker is up to temperature and put your flank steak on the cooking grate.
Plug your electric smoker in and turn the temperature to 200° F.
Fill the water tray if there is one.
Close the door.
Fill the pellet hopper with your choice of smoking wood pellets.
Plug in the pellet grill and run it through its start up process.
Once it is creating smoke, turn the temperature to 200° F.
When the pellet grill has come up to temperature, place your flank steak on the grill grates. Make sure your pellet grill is NOT set to DIRECT heat.
Never used a pellet grill before?
Check out this Ultimate Guide to Pellet Grills to learn why they are so easy and how to set one up for success every time.
Getting a Sear on a Pellet Grill
Pellet Grills work great for smoking large cuts of meat like brisket, pork butt, and ribs, and maintaining a near perfect consistent air temperature, much like the best competition smokers promise to do.
The downside is their ability to sear at high heat like you would over direct coals or a ripping hot propane gas burner.
In order to get the best of both worlds, we recommend coupling some Grill Grates with your pellet grill.
Grill Grates are specialty…well…grates that sit right over the existing grates on your pellet grill that help capture and direct all that ambient heat and give you a nice searing station in the corner of your pellet grill.
They claim to get temperatures up to 200°F HIGHER than the temperature you set your pellet grill, meaning even if your nice Traeger only goes up to 400°F on the control panel, you can still sear some steaks, pork chops, or chicken at 600°F at the beginning or end of the cook to give them a nice sear.
Make sure to measure the size of your current grilling area.
While you absolutely CAN cover your entire pellet grill with Grill Grates, like if you were doing a batch of burgers for a big party, in our case we only want to cover PART of the pellet grill, maybe 1/3 to 1/2 of the cooking area for our pellet grill smoked flank steak.
Gas or Charcoal Grill
On a charcoal grill you can use wood chunks just like you would in a charcoal smoker.
On a gas grill you will likely need to use a smoker box filled with wood chips, or a pellet tube smoker filled with wood pellets.
Think you need a fancy smoker to smoke food at home? Think again. Great smoked food can be made right on your current gas or charcoal grill.
If you are unfamiliar with these gas grill smoking devices mentioned above, no worries, we have you covered!
In the case of a smoked flank steak, we would opt for the pellet tube smoker since it will provide you with a longer smoking time without needing to refill multiple times like a smoker box.
However either one will work just fine depending on what you have available.
Set up your gas or charcoal grill for indirect cooking with the burners or a small amount of lit briquets on one side and plan for your meat to be on the other side.
Keep your vents closed about 75-90% on top and bottom to help maintain a low temperature.
Once the temperature of your grill is about 200° F, place your wood chunks, smoker box, or pellet tube smoker over the coals or lit burners and once smoke begins coming out, place your meat on the opposite side.
How to Carve and Serve a Smoked Flank Steak
Resting the Meat
After smoking and then reverse searing and bringing the internal temperature up to 130°F, you will remove the smoked flank steak from the smoker, grill, or broiler and let it rest.
NO NEED to tent loosely with foil or any other nonsense or it will overcook from its own residual heat.
Put it on a large plate or cutting board and “Fugget About It” for 15 minutes! Get the potatoes and sides ready or pour some drinks.
Let the smoked flank steak rest for at least this long before carving.
Carving the Smoked Flank Steak
Use a good meat slicing knife and cut the smoked flank steak in nice THIN strips, on a bias, against the grain.
Here’s a great tutorial if you need to educate yourself on this. Its a MUST with carving large steaks like flank steak.
You didn’t come this far just to cut it the wrong direction and leave your guests chewing each bite for minutes on end!
Using a good knife will also make life so much simpler. We particularly like this meat slicing knife from Mairico.
The outside slices may be more done than the very center if you have guests who prefer various levels of doneness.
What Other Foods Can I Smoke?
Looking for some more inspiration for things to smoke?
Check out some of our favorite recipes below that can easily be modified to be done on any grill or smoker.
More Smoked Beef
- Smoked Prime Rib on a Traeger Pellet Grill
- Perfect Smoked London Broil
- Smoked Ribeye Roast
- Hot and Fast Smoked Beef Brisket
- Smoked Corned Beef
- Smoked and Reverse Seared Ribeye Steaks
- Pellet Grilled Steak
- Perfect Grilled Hamburgers
- Smoked Eye of Round Roast Beef
- Pellet Smoked Baby Back Ribs
- Pellet Grill Smoked Pork Chops
- Smoked Fresh Ham with Dark Rum Citrus Glaze
- Spiral Sliced Smoked Hot Dogs
- Smoked Bratwurst with Beer Braised Onions
- Gas Grilled Bratwurst
- Pellet Grilled Bratwurst
- Roasted Pig in Your Backyard
- Traeger Smoked Pulled Pork
- Traeger 3-2-1 Pork Ribs
- Electric Smoker Pork Butt
- Pit Boss Pulled Pork
- Spatchcocked Chicken on a Pellet Grill
- Smoked Turkey Breast with Cajun Butter Injection
- Pellet Grill Whole Thanksgiving Turkey
- Spatchcock Smoked Turkey on a Pellet Grill
- Trash Can Turkey – OK, technically not made on a grill or smoker but one of the most fun ways there is to cook a Turkey…at over 700 degrees in only 2 hours!
- Honey Smoked Salmon
- Smoked Oysters in a Garlic White Wine Sauce
- Smoked Scallops with Lemon Butter Sauce
- Smoked Lobster Tails
- Honey Smoked Tilapia
- Perfect Smoked Halibut
- Smoked Mahi Mahi
- Smoked Swordfish Steaks
- Smoked Crab Legs with Cajun Clarified Butter
- Smoked Leg of Lamb with Guinness Marinade
- Smoked Lamb Chops with a Balsamic Butter Sauce
- Smoked Rack of Lamb with Garlic and Rosemary or Smoker
- Smoked and Pulled Lamb Shoulder with a Turkish Spice Rub
- Smoked Lamb Shanks
Other Odds and Ends
- Smoked Gouda Cheese
- Smoked Asparagus
- Smoked Cauliflower
- Sticky Smoked Sweet Potatoes
- Perfect Steamed Tamales
- Maple Bourbon Smoked Pineapple
Smoked and Reverse Seared Flank Steak
- Large shallow glass baking dish
- Propane, Electric, or Charcoal Smoker -OR-
- a Pellet Grill, Charcoal grill, or Gas grill with a smoker box or pellet tube smoker.
- Hickory, Pecan, or Mesquite Wood chips, chunks, or pellets
- Instant Read Thermometer
- Broiler or Hot Cast Iron Pan (optional)
- Foil Lined Baking Sheet (optional)
- 1.5-2 lb Flank Steak
- 1/2 Cup Olive Oil
- 1/3 Cup Worcestershire Sauce
- 1/3 Cup Soy Sauce
- 2 Tbsp White Vinegar Can also use rice wine vinegar
- 4-6 cloves Minced Fresh Garlic
- 1 Tbsp Tomato Paste
- 1/2 Cup Fresh green onions Chopped
Trim and Remove Silverskin
- Trim any excess fat from the edges of the flank steak.
- Remove the silverskin from the top and bottom broad sides of the flank steak.
Marinate the Flank Steak
- Whisk the marinade ingredients together in a small bowl and then transfer to a large sealable plastic bag.
- Place the flank steak in the bag and shake until all sides are covered in the marinade. You can also use a large covered glass baking dish if the flank steak is too big for a plastic bag.
- Place in the refrigerator for at least 4-6 hours or even overnight.
Set up the Grill or Smoker
- Remove your flank steak from the refrigerator but leave in the marinade until you are ready to place it on the smoker.
- Set up your smoker, pellet grill, or grill with indirect heat to 200-225°F.
- When the smoker or grill is up to 200°F, add your wood chunks to the coals, or wood chips the tray or smoker box. Alternatively, you can add wood pellets to a pellet tube smoker. Place the smoker box or pellet tube smoker over the hot coals or burners.
- When smoke begins to come out the vents, place your flank steak on the grate, away from the direct heat if using a grill.
Smoking the Flank Steak
- Monitor your flank steak internal temperature. After about 30-45 minutes your steak should reach an internal temperature of 110°F.
Prepare for Reverse Searing
- If you are using a grill, you can reverse sear the flank steak directly on the hot side of the grill. However, if you are using a pellet grill or smoker that does not provide direct heat, preheat your broiler with the top oven rack at its highest position.
- Alternatively, you can preheat a large cast iron pan with olive oil. Let it come up to medium to medium-high heat now and then crank to high later when time to sear the flank steak.
Reverse Searing the Smoked Flank Steak
- Once the flank steak reaches 110°F internally, either move it over to the HIGH direct heat side of the grill, place it on a foil lined baking sheet and position it under the preheated broiler, or place in the cast iron skillet on HIGH heat with olive oil.
- Cook the flank steak with HIGH direct heat for about 2-3 minutes on each side
- Remove the smoked flank steak from the direct heat and move it back to the indirect side of the grill or back into the smoker at 200°F until the internal temperature reads 130°F on an instant read thermometer for a medium level of doneness. (The internal temperature will rise another 5°F while resting.)
- Remove the flank steak from the grill or smoker and place on a large cutting board, uncovered to rest for 15 minutes before carving.
- Slice in thin strips, on a bias, against the grain of the meat with a good meat slicing knife. Serve immediately.