01 - Arrange the sliced onions and minced garlic evenly across the bottom of the slow cooker.
02 - Combine the smoked paprika, chili powder, ground cumin, salt, black pepper, and cayenne pepper in a small bowl. Rub the spice mixture thoroughly over all surfaces of the beef chuck roast.
03 - Place the seasoned beef chuck 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 the slow cooker and cook on the low setting for 8 hours, or until the beef is fork-tender and shreds apart effortlessly.
06 - Carefully remove the beef from the slow cooker and place it on a cutting board. Use two forks to pull and shred the meat into bite-sized pieces, discarding any large pieces of fat or gristle.
07 - Return the shredded beef to the slow cooker and stir to combine with the cooking juices. Cover and cook on low for an additional 15 to 20 minutes to reheat and allow the meat to absorb more flavor.
08 - Serve the pulled beef on burger buns topped with coleslaw, or over rice or in lettuce wraps for a lighter option.