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–+ servings
sliced leg of lamb roast on a white plate

Smoked Leg of Lamb with Guinness Marinade

Mads Martigan
Leg of lamb coated with a garlic and mustard rub and brushed with Guinness stout while slow cooked on a smoker or grill. A complex, flavorful, and rich lamb roast perfect for a holiday or special occasion.
Whether you are using a pellet grill like a Traeger, Camp Chef, or Pit Boss, an electric smoker like a Masterbuilt, or just a conventional propane grill like a Weber, we've got you covered. 
5 from 2 votes
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Prep Time 1 hour
Cook Time 2 hours 30 minutes
Total Time 3 hours 30 minutes
Course Main Course
Cuisine American, Irish
Servings 8 Servings
Calories 515 kcal

Equipment

  • Smoker or Grill
  • Wood Chips, Pellets, or Chunks, preferably hickory or fruitwood

Ingredients
  

  • 1 5-7 lb Leg of Lamb preferably a boneless upper sirloin cut
  • 2 tablespoon Olive oil
  • ¼ cup Dijon Mustard
  • 8 cloves Garlic, freshly minced
  • 2 tablespoon Fresh Thyme, Chopped
  • 2 tablespoon Fresh Rosemary, Chopped
  • ¼ Cup Kosher Salt
  • 2 tablespoon Black Pepper
  • 1 Can Guinness Stout, room temperature or any beer of your choice, preferably a dark ale, porter, or other stout.
  • 2 tablespoon Honey

Instructions
 

Prepare the Lamb

  • Place the lamb in a foil pan and trim Lamb of any excess fat.
  • Mix the oil, mustard, garlic, thyme, rosemary, salt, and pepper in a bowl until thoroughly incorporated.
  • Rub the entire outside of the lamb with the mustard and garlic mixture.
  • Cover with plastic wrap and let marinate in the refrigerator at least 2 hours before preparing the smoker, preferably overnight.

Set up the Smoker

  • Light the smoker or set up the grill for indirect cooking with a smoker box and preheat to between 225-250° F.
  • Once the smoker/grill is up to temperature and smoke is being produced, place the lamb on the smoker.
    leg of lamb to smoke
  • Insert an internal probe thermometer and close the lid, maintaining a cooking temperature of 225-250 deg F.
    ;eg of lamb with a temperature probe
  • A 5-7 lb boneless leg of lamb will take roughly 2-3 hours to cook at 250° F. Anticipate longer for a bone-in leg.

Brush with Guinness and Honey

  • Pour the stout and honey into a large measuring cup and whisk until fully dissolved.
  • Brush the lamb with it when you first place it on the smoker and then again every 20 minutes or so during the cook.

Smoking the Leg of Lamb

  • When the thickest part of the lamb reads between 138-145° F internally, depending on your doneness preference, remove the lamb from the smoker.
  • Place in an aluminum pan to catch any drippings and excess marinade, leave uncovered and let rest for 15 minutes.

Serving the Smoked Lamb

  • Slice the lamb in ¼ inch thick slices and serve immediately. Spoon any drippings from the pan over the lamb as you serve.
    slicing a leg of lamb

Nutrition

Calories: 515kcal
Keyword bbq, Charcoal, Garlic, Grilled, Lamb, Leg of Lamb, Marinade, Mustard, smoked, wood smoke
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