Preheat the grill to 230°F. Trim the pork butt, leaving at least 1/4 inch of fat to protect the meat from drying out while cooking. Score the fat on the pork, then slather it in yellow mustard as a binder. Season the pork evenly on all sides with BBQ rub.

Place the pork directly on the grill grates with the fat cap facing down. After 90 minutes, begin basting the pork butt with BBQ sauce every 10-15 minutes. Continue cooking until the internal temperature reaches 145-155°F.

When the internal temperature hits 145-155°F, remove the pork from the grill. Lay out two layers of aluminum foil or butcher paper. Using heat-resistant gloves, place the pork on top of the foil. Wrap it tightly with the temperature probe still inserted, then return it to the grill.

Cook for approximately 2.5 hours until the internal temperature reaches 195-203°F. Remove the pork from the grill and let it rest for 30 minutes in an aluminum pan (wrapped or unwrapped). The meat is ready when the shoulder bone pulls out clean or when a fork twists through the meat easily.

For pulled pork: Use two forks, heat-resistant gloves, or meat claws to shred the meat to your desired consistency. Taste and add additional seasoning or BBQ sauce if desired.

For sliced pork: Simply slice the pork butt into portions and serve.