01 - In a small bowl, combine kosher salt, black pepper, smoked paprika, garlic powder, onion powder, and ground cumin. Rub the mixture evenly over the entire surface of the beef chuck roast.
02 - Place the thinly sliced yellow onion and minced garlic at the bottom of the slow cooker. Lay the seasoned beef roast on top of the aromatics.
03 - Whisk together beef broth, barbecue sauce, apple cider vinegar, and Worcestershire sauce in a separate bowl. Pour this mixture evenly over the beef in the slow cooker.
04 - Cover and cook on low heat for 8 hours, or until the beef becomes tender enough to shred easily with forks.
05 - Remove the beef from the slow cooker and shred it thoroughly using two forks. Skim excess fat from the remaining cooking liquid, then return the shredded beef to the slow cooker and stir to coat with the juices.
06 - Toast sandwich buns if desired. Pile the pulled beef onto buns and top with additional barbecue sauce, coleslaw, and pickles as preferred. Serve immediately while hot.