01 - Pat the beef roast dry with paper towels and season all sides generously with kosher salt and black pepper.
02 - Arrange the sliced yellow onion and minced garlic evenly across the bottom of the slow cooker insert.
03 - Place the seasoned chuck roast on top of the onion and garlic bed.
04 - In a medium bowl, whisk together beef broth, barbecue sauce, Worcestershire sauce, apple cider vinegar, brown sugar, smoked paprika, and chili powder until fully combined.
05 - Pour the sauce mixture evenly over the beef roast in the slow cooker.
06 - Cover with the lid and cook on LOW setting for 8 hours (or HIGH for 4-5 hours) until the beef is fork-tender and easily shreds apart.
07 - Transfer the cooked beef to a large bowl and shred using two forks, discarding any large pieces of excess fat as you work.
08 - Skim any excess fat from the cooking liquid remaining in the slow cooker, then return the shredded beef and toss thoroughly with the juices.
09 - Pile the hot pulled beef onto sandwich buns and top with coleslaw, pickles, or additional barbecue sauce as desired.