Pizza Casserole(Teacher'S Favorite) - cooking recipe

Ingredients

1 pkg. sliced pepperoni (4 oz.)
1 medium onion, chopped
1/3 c. melted butter
6 oz. thin spaghetti, cooked
1 c. (4 oz.) grated Swiss cheese
2 (8 oz.) cans tomato sauce
1 lb. Mozzarella cheese, sliced
1 (4 oz.) can sliced mushrooms, drained
1/2 tsp. oregano
1/2 tsp. basil

Preparation

Boil pepperoni for 5 minutes in enough water to cover; drain. Saute onion in 1 1/3 tablespoons butter.