Remove the steaks from the refrigerator about 20 minutes before cooking to take off the chill. Pat each side with salt, pepper and garlic powder.
Preheat the smoker to 225°F.
Smoke the steaks until they are 10 to 15 degrees below your target temperature, about 40-50 minutes for medium-rare (pull at 115 to 120°F). Allow to rest for 10 minutes before searing.
Near the end of the smoking time, heat a cast iron skillet over high heat until smoking, or pre-heat your grill to high heat.
Sear the steaks in the skillet or on the grill, 60 to 90 seconds per side, then hold them on their edge to render the fat cap.
If searing in a skillet, add the butter, garlic and herbs, and baste over the top of the steak for a few seconds. If searing on the grill, the butter, garlic and herbs can be added to a small skillet and heated over medium heat for 1-2 minutes, then poured over the top of the steak before serving.
Rest 5 minutes, slice against the grain and serve.
Notes
Cook to temperature, not time. Thicker or bone-in steaks will take longer.