Slice top from a fat loaf of French bread. Hollow the loaf out, leaving a 1 plus inch thick wall. Whirl discarded bread in blender or food processor for crumbs.
Brown 1 1/2 pound hamburger and drain. Add the onion, mushrooms, green pepper, soy, mustard, oregano, salt, and pepper. Saute. Cool slightly. Add the egg and the bread crumbs from the hollowed out loaf. Combine all with cheese and milk if needed.
Fill French bread with hamburger mixture. Wrap in foil. Bake for 20 minutes at 350 degrees. Serve in slices.
