Preheat your smoker to 250°F using a combination of hickory and cherry wood.
Remove the boneless pork butt from the packaging and pat it dry. Trim away any loose pieces or thick pockets of excess fat, then cut it into two evenly sized roasts.
8 lb boneless pork butt
If one roast unfolds after cutting, tie it with butcher's twine to create a more uniform shape for even cooking.
Lightly coat each roast with yellow mustard. Season all sides generously with the The Rub, using about 3 tablespoons of rub per roast (approximately 6 tablespoons total).
2 tablespoons yellow mustard, 6 tbsp The Rub
Place the pork on the smoker and insert a temperature probe into the thickest part of each roast. Smoke until the bark is well developed and a deep mahogany color, about 5 hours.
Wrap each roast tightly in pink butcher paper, reinsert the temperature probes, and return them to the smoker.
Continue cooking until the pork is probe tender, usually around 200°F to 205°F. The probe should slide into the meat with little to no resistance.
Remove the pork from the smoker and let it rest, still wrapped, for at least 1 hour.
Unwrap the pork, shred it while it's still warm, mixing the bark throughout the meat. Serve immediately or use in your favorite pulled pork recipes.