Brown hamburger until almost done and drain off fat. Place meat back in pan with the onion (and green pepper if you want) and finish browning and cooking the onion. If there is any fat left after the browning is complete, drain.
In large mixing bowl add the beans, brown sugar, ketchup, mustard and worcestershire sauce. Add the beef mixture and stir all the ingredients together until mixed well.
Pour the beef/bean mixture into a large casserole dish and bake in a 350 oven until bubbly. Serve with cornbread.