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 cloves in an even layer at the bottom of the slow cooker insert.
03 - Place the seasoned chuck roast directly on top of the onion and garlic bed.
04 - In a medium bowl, whisk together the beef broth, barbecue sauce, Worcestershire sauce, apple cider vinegar, brown sugar, smoked paprika, and chili powder until fully combined and smooth.
05 - Pour the prepared 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 on HIGH for 4-5 hours, until the beef is very tender and easily shreds apart with a fork.
07 - Transfer the cooked beef to a large bowl or cutting board. Use two forks to shred the meat, discarding any large pieces of excess fat as you work.
08 - Skim any excess fat from the surface of the cooking liquid in the slow cooker. Return the shredded beef to the cooker and toss thoroughly with the remaining juices to absorb flavor.
09 - Heap the juicy pulled beef onto sandwich buns and top with coleslaw, sliced pickles, or additional barbecue sauce as desired. Serve immediately while warm.