01 - Arrange the sliced onions and minced garlic evenly across the bottom of the slow cooker.
02 - In a small bowl, combine smoked paprika, chili powder, ground cumin, salt, black pepper, and cayenne pepper. Rub the spice mixture thoroughly over all surfaces of the beef chuck roast.
03 - Place the seasoned roast on top of the onions and garlic in the slow cooker.
04 - Pour the barbecue sauce, beef broth, apple cider vinegar, and Worcestershire sauce evenly over the beef.
05 - Cover and cook on low for 8 hours, or until the beef is fork-tender and pulls apart effortlessly.
06 - Transfer the roast to a large cutting board and shred using two forks, discarding any large pieces of fat.
07 - Return the shredded beef to the slow cooker and stir to coat evenly in the sauce. Cook on low for an additional 15–20 minutes to reheat and allow the meat to absorb flavor.
08 - Serve the pulled beef on burger buns topped with coleslaw, over rice, or in lettuce wraps. Drizzle with extra barbecue sauce as desired.