Preheat oven to 425°F. Line a baking sheet with aluminum foil. Trim brisket of excess fat. Over the entire surface, evenly sprinkle salt, pepper, and barbecue seasoning, pressing firmly. Place on the prepared baking sheet, and bake uncovered 30 minutes.
To the Crockpot, whisk together broth, ½ cup of the barbecue sauce, Worcestershire sauce, soy sauce, and liquid smoke. Transfer the brisket to the Crockpot, cover, and cook on low for 7-8 hours, flipping over halfway through cooking time.
Pierce with a fork, and if the brisket doesn’t have a tender pull, cook an additional 1-2 hours.
Preheat the oven to broil. Line a baking sheet with aluminum foil, and transfer over the cooked brisket. Brush with ¼ cup of the barbecue sauce on top, and broil 5 minutes. Gently flip the brisket, brush with remaining ¼ cup barbecue sauce, and broil 5 additional minutes.
Transfer brisket to a cutting board, rest 5 minutes, then slice against the grain or chop. Serve with additional barbecue sauce and your favorite sides.