Pat dry and season with salt, pepper, and garlic powder evenly on all sides of the roast. Use additional seasoning if needed to coat the entire tri tip, it will vary depending on the size. If you prefer, you can use steak seasoning instead of the seasonings mentioned.
Set the smoker to 200*F and smoke for 2-3 hours until you have an internal temperature between 125-130*F. (Rare)
Remove the tri-tip and increase the pellet grill temperature to 500*F.
Place a cast iron skillet on the smoker grates. Once the grill gets to temperature, add the butter to a very hot cast-iron pan and transfer the tri-tip back into the pan. Sear for 30 seconds on each side. Do not let the internal temperature go beyond 140*F.
Rest the tri-tip for 10 minutes before slicing against the grain and serving.
Notes
Oak, Hickory or Mesquite Pellets work best for this recipe.