Cut chuck roast into 2-inch pieces. Place onion and garlic in the bottom of a 6-quart or larger slow cooker.
Add beef chunks. Sprinkle salt, pepper, paprika, and crushed red pepper flakes over beef. Add bay leaves.
Pour Worcestershire sauce, apple cider vinegar and beef broth over pork.
Cover slow cooker and cook on LOW for 8 hours or on HIGH for 5 hours.
Remove the beef pieces with a slotted spoon and place them on a rimmed baking sheet lined with aluminum foil.
In a bowl stir together BBQ Sauce, A1 Sauce, and brown sugar.Pour mixture over beef pieces.Broil until crispy, about 5 minutes, watching carefully so it doesn't burn.
Notes
Use your favorite store-bought or homemade bbq sauce for this recipe. I like to use a fairly thick one that is both sweet and spicy, like Sweet Baby Rays.