Spaghetti Casserole - cooking recipe

Ingredients

1 chopped onion
1 stick butter
vermicelli spaghetti, cooked and drained
1 can extra crunchy spaghetti sauce
1 lb. ground beef, browned and drained
2 cans mushrooms
4 oz. Mozzarella cheese
4 oz. Cheddar cheese
4 oz. Swiss cheese
2 pkg. pepperoni

Preparation

Layer in dish in order listed.
Bake at 350\u00b0 for 20 minutes.