Once the steaks reach 100-110°F internally, remove the smoked ribeye steaks from the smoker onto a platter and bring them over to the preheated cast iron skillet.
Turn the heat on the skillet up to HIGH and when the oil begins to smoke put one of the steaks in the skillet.
Let the steak sear for about 60-90 seconds on one side and then flip to the other side.
Check the internal temperature of the steak, continue to flip in the skillet to cook evenly and when it is about 5°F shy of your desired doneness (see notes below), remove it from the skillet.
Add another 2 Tbsp of butter and 1 Tbsp oil to the hot skillet and repeat with the remaining steaks.
Let all the steaks rest 5-10 minutes before serving. Do not cover them in foil or stack them as they will overcook.