Preheat grill or smoker for a 225 degree F. low and slow cook of 5-6 hours. Use wood or pellets of choice.
Blot ribs dry with paper towels. Remove the membrane from the back, and cut off any large knobs of fat and hanging pieces of meat.
Brush ribs with a little oil or mustard. Apply rub evenly onto the ribs. You only need what sticks to the ribs and no more. Don't overpack the rub.
Place ribs in the grill and smoker, close lid, and let it go. Watch for temperature fluctuations and adjust accordinglyAfter the 3rd hour, wrap the ribs in aluminum foil, along with 2 tablespoons chopped butter, 1/4 cup of brown sugar, and 1/4 cup of apple juice. Place wrapped ribs back onto the grill for 2 hours.
After two hours, unwrap the ribs and place back onto the grill grates for another hour. Apply barbecue sauce every 15 minutes until they register an internal temperature between 195-200 degrees F.
Carefully remove from the grill or smoker, and place onto a large cutting board. Tent with foil, and let them rest for 20 minutes. Cut into individual ribs and enjoy.