Slice your pork butt into steaks, then chop those steaks into cubes about 1½” thick.
Coat the cubes of pork in olive oil (or yellow mustard).
Season the cubes of pork on all sides with pulled pork bbq rub, being sure they are well-coated.
Lay the cubes out onto a jerky tray or wire rack, leaving about 1½” of space between each one.
Leave the tray on your counter at room temperature while you fire up your smoker.
Preheat your smoker to 250°F.
Place the wire rack directly on the grates and let them smoke for 2½-3 hours, or until a nice bark has formed and the internal temperature is between 165°F and 175°F.
In a medium-sized mixing bowl, combine the bbq sauce and melted butter.
Transfer the pork butt burnt ends to an aluminum tray and pour the barbecue sauce mixture on top.
Give the pan a good shake until each burnt end is well-coated in sauce.
Sprinkle the brown sugar all over the top of the burnt ends. Cover the entire pan tightly in aluminum foil.
Place the pan back on the smoker for another 1-1½ hours, until the internal temperature is over 200°F.
Let rest at room temperature for 20-30 minutes, then serve and enjoy!