Preheat oven to 350 and lightly grease a 9 x 9 round or square pan with cooking spray. Cook pasta according to package directions. Once mac and cheese is prepared, stir in cooked bacon. Spread mac and cheese out into prepared pan. Combine bread crumbs and melted butter until well coated, then sprinkle topping over mac and cheese. Bake at 350 for 15-20 minutes or until topping is golden brown.