Baked Spaghetti without drippings curd

1 cup chopped onion 1 cup chopped green pepper 1 tablespoon butter 1 can 28-oz diced tomatoes undrained 1 can (4oz) mushroom stems and pieces, drained 1 can[...]

1 cup onion , chopped 1 cup green pepper , chopped 1 tablespoon butter 1 (28 ounce) can tomatoes , with liquid cut up 1 (4 ounce) can mushroom stems and[...]