Prep Time: 10
Cook Time: 50
Serves: Serves: 4
Preheat oven to 350°F. Coat 2-quart casserole with nonstick cooking spray; set aside. Prepare macaroni according to package directions, omitting salt. During last 5 minutes of cooking add onion, bell pepper and celery. Drain pasta and vegetables.
While macaroni is cooking, combine Ricotta, Swiss, Cheddar, milk, egg whites, flour, butter, salt, black pepper and pepper sauce in food processor or blender; process until smooth. Stir cheese mixture into pasta and vegetables.
Pour mixture into prepared casserole. Bake 35 to 40 minutes or until golden brown. Let stand 10 minutes before serving.