In a large skillet on medium high heat, cook ground beef and onion with a small bit of margarine until browned.
While the meat is cooking, in a bowl combine the ketchup, worcestershire, brown sugar and onion powder.
Pour the sauce over the meat mixture and mix well. Continue cooking for 3-4 minutes.
Butter both sides of the toast. In a casserole dish place 6 slices of bread down. Spread 2 cups of cheese over the first layer of bread. Add in the meat mixture and spread evenly. Then spread the remaining cheese and top with the other 6 slices of bread.
Bake for 25-30 minutes until the bread has a golden color on the top. Slice in ½ and enjoy!