1 can beef hash or corned beef hash (well chilled) slice about 1/2 inch thick Place in well greased baking dish. Brush each slice with prepared mustard. On each slice, place a slice of tomato and sprinkle with salt and pepper. Top those with finely chopped onions. Sprinkle with your favorite bread crumbs. Dot with pieces of butter or margarine. Bake @ 375 degrees for 25-30 min.