Preheat your oven to 300°F.

In a large oven-safe pot, heat the olive oil over medium heat. Add the diced onion and sauté until translucent, about 5 minutes. Stir in the minced garlic and cook for another minute until fragrant.

Season the beef chuck roast with salt, black pepper, and cayenne pepper (if using). Place the roast in the pot with the onions and garlic.

In a bowl, mix together the beef broth, barbecue sauce, Worcestershire sauce, and brown sugar. Pour this mixture over the beef.

Cover the pot with a lid and transfer it to the preheated oven. Cook for 3 to 4 hours, or until the beef is tender and easily shreds with a fork.

Remove the pot from the oven and let it cool slightly. Shred the beef using two forks, mixing it with the sauce in the pot.

Toast the hamburger buns if desired. Serve the pulled beef on the buns, topped with coleslaw if you like.