01 - Preheat oven to 300°F.
02 - In a small bowl, combine brown sugar, smoked paprika, kosher salt, black pepper, garlic powder, onion powder, and cayenne pepper. Pat beef dry with paper towels and rub spice mixture evenly over the entire roast.
03 - Place seasoned beef in a large Dutch oven or roasting pan. Pour beef broth, apple cider vinegar, Worcestershire sauce, and Dijon mustard around the base of the meat, avoiding direct coverage.
04 - Cover tightly with lid or aluminum foil. Roast for 4 to 4.5 hours until beef is fork-tender and easily shreds apart.
05 - While beef roasts, combine ketchup, apple cider vinegar, brown sugar, molasses, Worcestershire sauce, smoked paprika, garlic powder, and onion powder in a saucepan. Simmer over medium-low heat for 15 minutes, stirring occasionally. Season with salt and pepper to taste.
06 - Transfer cooked beef to a large bowl. Using two forks, shred meat, discarding any excess fat pieces.
07 - Skim fat from the braising liquid. Add 1/2 cup of the defatted liquid to the shredded beef for moisture. Fold in half of the prepared BBQ sauce, reserving the remainder for serving.
08 - Lightly toast the buns if desired. Heap sauced beef onto bottom buns, top with coleslaw and pickles. Drizzle with additional BBQ sauce as preferred.
09 - Serve sandwiches immediately while warm.