How to Make It
Place brisket in a large shallow dish or extra-large, heavy-duty zip-top plastic bag; pour liquid smoke over brisket. Sprinkle evenly with onion, garlic salt, and salt. Cover or seal, and chill 8 hours, turning occasionally.
Remove brisket, and place on a large piece of heavy-duty aluminum foil, discarding liquid smoke mixture. Pour Worcestershire sauce evenly over brisket, and fold foil to seal; place wrapped brisket in a roasting pan.
Bake at 275° for 5 hours. Unfold foil; pour barbecue sauce evenly over brisket. Bake 1 more hour, uncovered.