Remove the membrane from the back of the ribs and trim off any loose pieces of meat.
Season both sides of the ribs with the dry rub and let them sit at room temperature for 30 minutes.
Set up your pellet grill for smoking at 225F with hickory pellets.
Smoke the ribs for two hours.
Prepare the foil pouch with the margarine and brown sugar.
Place the ribs, meat side down into the foil pouch, add the apple juice and tightly seal.
Return the ribs to the grill, meat side down, and cook at 225F for another two hours.
Remove the foiled ribs from the grill and carefully open the aluminum foil to release the hot steam.
Return the ribs to the grill, meat side up, and baste with barbecue sauce.
Cook the ribs for one more hour until they are tender enough for a toothpick to slide through the meat.
Remove the ribs from the grill, place meat side down on a cutting board and slice cleanly between the bones.