Preheat your pellet grill to 225°F. Season the steak liberally with the SPG.
Place the tri-tip into the preheated grill, close the lid, and let it cook until the roast is 10 degrees under your desired finished temp. (See notes below for chart on when to pull it off.)
In a large cast-iron skillet placed on the stovetop, heat the pan over high heat.
Place half of the butter in the pan and immediately place the steak in.
Add the other half of the butter before you flip. Get a good sear on all sides of the roast.
Pull out of the pan and let rest for 10-15 minutes before slicing across the grain.
Notes
PULL OFF THE GRILL AT THE FOLLOWING TEMPS DURING THE SMOKE PORTION OF THE COOK: