Place the pork butt roast on a clean cutting board. If your roast still has skin or a thick layer of fat, trim that down to 1/4 inch layer of fat cap remaining.
Rinse the roast under cold running water and pat completely dry with paper towels.
Place the roast inside a disposable foil roasting pan.
When working with raw pork, make sure you clean all the surfaces it comes in contact with hot soapy water, including the board, the sink, and your hands to avoid any cross-contamination.
In a small bowl, combine the sugar, salt, paprika, pepper, onion powder, garlic powder, and cayenne.
Rub the entire pork shoulder with mustard to coat it. Pat the pork butt rub mixture into the mustard to coat the entire roast.
Cover the pan well with plastic wrap.
Place the seasoned pork in the refrigerator for 8 to 12 hours or overnight.
Remove the roast from the refrigerator 40 minutes before turning your smoker on.
After the meat has come to room temperature, remove the plastic wrap and pour off any accumulated liquid in the bottom of the pan.
Set up and preheat your smoker to 225°F.
If using a pellet grill, fill the hopper with pellets and ignite the grill with the top open.
Close the top and preheat for 5 minutes. In an electric smoker, fill the water bowl half way and place wood chips in the tray. Open the top vent, close the door, and preheat for 5 minutes.
Place the pork shoulder directly on the smoker rack.
Insert the probe thermometer into a thick portion the roast (if a thermometer is attached). In an electric smoker, place a clean disposable pan on the rack below the roast to catch fat drippings.
Replenish the pellets or wood chips and water as needed.
Spray the pork with some vinegar every 2 hours. At 8 hours, check the internal temperature of the meat.
You are looking for at least 190°F. The sugar in the rub should have caramelized into a dark crust.
If the meat isn’t quite up to temperature, wrap it really well in aluminum foil and place it back in the smoker for approximately 1 additional hour.
Place the roast on a clean cutting board and allow it to rest for rest for at least 25 minutes until the meat is cool enough to handle so that it can be removed from the bone.
Resting the meat before shredding it is an extremely important step. Not doing this can result in all the juices running out and the pork becoming dry and chewy.
Once the pork has cooled enough to touch, shred or pull the meat using 2 forks.
Place the pulled pork and any juices on a large serving platter with some tongs for everyone to help themselves.
Serve with your favorite barbecue sauce, rolls, and coleslaw.