Coat a large 6-quart slow cooker with cooking spray. Line the bottom with the thinly sliced onions. Pour in the apple juice and minced garlic.
In a small bowl, whisk together the brown sugar, chili powder, paprika, garlic powder, onion powder, mustard powder, ground cumin, salt, and pepper (I add 1 tablespoon salt and 1 heaping teaspoon pepper, adjust to your preference). Remove pork from packaging and dab all over with a paper towel. Rub the spices into the pork on all sides.
Place the pork on top of the onions; if there is a white layer of fat, place that facing up (the fat will render down and make the pork more tender).
Cover and cook for 8–11 hours on low setting. I don’t recommend cooking on high. (In my slow cooker, a 5.5-pound roast is typically perfect at 9 hours. Yours may vary slightly.)
Once the pork is fully cooked and shreds easily, remove it from the slow cooker and transfer to a large platter or cutting board. Carefully drain the liquid from the slow cooker. Let the pork cool slightly, then pull off the top layer of fat (it should come off easily) and remove the bone. Discard both. Use two forks to shred the pork, removing any large pieces of fat as you go. Return the shredded pork to the slow cooker and use tongs to mix in your desired amount of BBQ sauce (see note 2) until the pork is evenly coated.
Spread butter on the insides of the buns. Add to a skillet or griddle and lightly brown the buns over medium heat.
Top the bottom bun with a generous amount of the BBQ pulled pork and a big spoonful of coleslaw. If desired, add pickles. Add top bun and serve right away.
Video
Notes
Note 1: This recipe is written for a 4.5 to 6.5 lb bone-in pork butt roast. If using a larger cut (like 8–9 lbs), make sure it fits in your slow cooker and increase the seasonings. For an 8 lb roast, I use 1-1/2 times the seasoning mix.Note 2: You can use your favorite BBQ sauce or make my homemade chipotle-honey BBQ sauce. Combine in a blender:
1 cup ketchup
½ cup brown sugar
⅔ cup + 1 tablespoon honey
1½ tablespoons apple cider vinegar
2 teaspoons Worcestershire sauce
1 teaspoon minced garlic
1 to 2 tablespoons chipotle peppers in adobo
2 tablespoons adobo sauce
¼ teaspoon each salt and pepper
Blend until smooth, then taste and adjust. (If using fewer peppers, you'll want to reduce the honey so it isn't too sweet.)Heat level guide:
Note 3: You can make coleslaw from scratch or use a shortcut. For a quicker version, toss a bag of coleslaw mix with fresh refrigerated dressing like Litehouse or Marie’s.Storage: Keep leftovers in an airtight container in the fridge for up to 5 days. Freeze for up to 3 months. Thaw overnight in the fridge and reheat before serving.