01 - Arrange the sliced onions and minced garlic evenly across the bottom of the slow cooker.
02 - In a small bowl, combine the 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 - Set the seasoned roast on top of the onion and garlic bed in the slow cooker.
04 - Pour the barbecue sauce, beef broth, apple cider vinegar, and Worcestershire sauce evenly over the beef.
05 - Cover the slow cooker and cook on low for 8 hours, or until the beef is fork-tender and pulls apart easily.
06 - Transfer the beef to a cutting board and shred using two forks, discarding any large pieces of fat.
07 - Return the shredded beef to the slow cooker and stir well to coat with the sauce. Cook on low for an additional 15 to 20 minutes to allow the meat to reheat and absorb the flavors.
08 - Serve the pulled beef on burger buns topped with coleslaw, or over rice or in lettuce wraps for a lighter option.