Pizza Casserole
["4 oz. pepperoni, sliced", "1 medium onion, chopped", "1/3 c. melted butter", "6 oz. cooked thin spaghetti", "1 c. or 4 oz. grated Swiss cheese", "16 oz. grated Mozzarella cheese", "16 oz. tomato sauce", "fresh mushrooms or 1 can drained mushrooms", "1/2 tsp. oregano", "1/2 tsp. basil"]
["Saute onion in 1 1/3 tablespoons butter.", "Preheat oven to 350\u00b0.", "Pour remaining 1/3 cup butter into an 11 x 7 x 2-inch baking dish.", "Toss cooked spaghetti in butter.", "Cover spaghetti with 1/2 tomato sauce, Swiss cheese, 1/2 pepperoni, 1/2 Mozzarella and all of mushrooms and onion.", "Sprinkle with oregano and basil. Top with remainder of tomato sauce, cheese and pepperoni.", "Bake 20 to 25 minutes."]
["pepperoni", "onion", "butter", "Swiss cheese", "Mozzarella cheese", "tomato sauce", "mushrooms", "oregano", "basil"]