If your roast is frozen, thaw it completely before preparing.
With a sharp knife, score the fat cap in a criss-cross pattern. Leave about an inch between each cut.
Most cuts of pork loin will come trimmed and tidy. If necessary, trim off the extra fat and any silver skin and connective tissue.
Pat the roast dry with a paper towel. Drizzle the roast with olive oil or mustard to give the dry rub something to stick to Cover the entire surface with the rub. Make sure to get it into the gaps of the scoring cuts. Then place in the fridge for 15-30 minutes or overnight if you have the time.
Choose your preferred pellets and load up the grill hopper. For this recipe, we used Applewood pellets.
Preheat the pellet grill to 165°F. Close the lid and run for 15 minutes.
Place the pork, with the fat cap side up, directly on the grill grates. Insert the meat temperature probe at this point, to check the internal temps. Close the lid. Smoke at 165°F for the first 1½ to 2 hours then up to 250F until internal temp hits 150F (about 2-3 more hours).
Once the pork reaches 150°F, remove it from the grill.
Place on a cutting board or platter and let the pork loin rest for 15-20 minutes.