Cut the beef chuck roast in half and place it in a 3- or 4-quart slow cooker. Editor's Tip: For an extra layer of flavor, consider browning the beef in a hot skillet before adding it to the slow cooker.
In a small bowl, combine the ketchup, brown sugar, barbecue sauce, Worcestershire sauce, dijon mustard, liquid smoke (if using), salt, garlic powder and pepper. Whisk these ingredients together until they form a smooth, well-blended sauce.
Pour the sauce mixture over the beef in the slow cooker. Cover and cook on low for 8 to 10 hours or until the meat is tender.
Remove the meat from the slow cooker and let it cool slightly. While the meat is cooling, skim any excess fat from the surface of the cooking liquid. Using two forks, shred the cooled beef.
Return the shredded beef to the slow cooker with the remaining sauce. Cover and cook for an additional 15 minutes on low or until heated through.
Using a slotted spoon to drain excess liquid, place about ½ cup of the pulled beef mixture on each sandwich bun. If desired, top with sliced onions, dill pickles and pickled jalapenos. Editor's Tip: Lightly toast the buns for an extra crunch and to prevent the buns from getting soggy.
