- Fire up your Pit Boss Platinum Series KC Combo on SMOKE mode and let it run with lid open for 10 minutes then set it to 225° F. If using a gas or charcoal grill, set it up for low, indirect heat.
- Rub the mustard all over the tri tip, then season with Prime Beef Rub.
- Place the tri tip directly on the grill grates and smoke until the internal temperature reaches 165° F (about 2 1/2 hours).
- Remove the tri tip from the grill and wrap it in Pit Boss Peach Butcher Paper. Return the tri tip to the grill and continue to smoke until the internal temperature reaches 200° F (an additional 2 ½ to 3 hours).
- Remove the tri tip from the grill, and rest for 30 minutes, or rest and refrigerate overnight.
- Increase the grill temperature to 275° F.
- Cube into ½ inch to ¾ inch pieces, then place cubed tri tip in a large cast iron skillet.
- Stir together BBQ sauce, Dr. Pepper, honey, and worcestershire sauce in a jar or mixing bowl, then pour over the cubed tri tip. Dot with butter, then sprinkle brown sugar over the top.
- Place skillet on the grill grate, over indirect heat. Cook for 1 ½ to 2 hours, rotating pieces halfway through cooking. Sauce will have reduced, coated and slightly char the tri tip. Remove from the grill and serve warm.