Prepare the Pork: Pat the pork shoulder dry with paper towels. Rub it with mustard and olive oil to help the seasoning stick.
Seasoning: In a small bowl, mix salt, black pepper, smoked paprika, garlic powder, onion powder, cayenne, and brown sugar. Rub the mixture all over the pork.
Slow Cook: Place sliced onions and garlic at the bottom of the slow cooker. Add the seasoned pork on top.
Add Liquid: Pour apple cider vinegar, chicken broth, Worcestershire sauce, and barbecue sauce over the pork.
Cook Low & Slow: Cover and cook on low for 8-10 hours (or high for 5-6 hours) until the pork is fork-tender and easily shreds.
Shred the Pork: Remove the pork and shred it using two forks. Mix it back into the juices for extra flavor.
Serve: Enjoy in sandwiches, tacos, or alongside coleslaw and cornbread.
Notes
For a smokier flavor, add a teaspoon of liquid smoke or cook the pork in a smoker at 225°F for 8-10 hours.