Stir together the rub ingredients until completely combined. Use all of the rub mixture to season the pork butt. Wrap tightly in plastic wrap and let “cure” in the fridge for at least 4 hours, but better overnight. About an hour before cooking, remove from the refrigerator to take the chill off the meat.
Set up grill for indirect cooking with medium-low heat (temperature around 300°F). Add onions to the drip pan and place under the grates where the pork will sit and return grates to the grill. Place the pork, fat side up, over the drip pan and close the cover. Total cooking time will be 4 to 6 hours depending on the size of the roast and how often the grill cover is opened. The pork will be ready and falling off the bone tender when the internal temperature reaches 195°F.
Remove the roast from the grill and wrap in aluminum for 15 to 20 minutes. Meanwhile, remove the drip pan from the grill and the onions from the pan. Drain the pan dripping and spoon off the fat. Combine BBQ sauce, cranberries, and de-fatted pan drippings to a saucepan and bring to a simmer.
Unwrap the pork and cut away the fat cap and any pieces of skin and excess fat. Using your hands or a couple of forks, pull meat into strands ¼- to ⅛-inch wide and a couple inches long. Transfer pork and any juices to mixing bowl and ladle in some sauce. Toss to coat adding more sauce if desired. Serve hot or at room temperature on buns with extra sauce.
Recipe by Grilling Outdoor Recipes powered by Bull Outdoor Products at http://www.grillingoutdoorrecipes.com/extra-cranberry-sauce-pulled-pork-with-cranberry-bbq-sauce/