Prepare elbow macaroni according to package directions; drain. In medium skillet, cook bacon until crisp; drain. In large bowl, combine macaroni, bacon, cheeses, bread cubes, onion and green pepper. In medium bowl, beat together egg yolks, milk, salt and hot pepper sauce. Add to macaroni mixture; mix well.
In large bowl, beat egg whites until stiff. Fold into macaroni mixture. Put into buttered 12 inch quiche dish or a 13x9 inch baking dish. Place a shallow baking dish with 1-2 inches water on lowest rack of a 325° F oven. Place quiche on center rack. Bake until set and knife inserted in center comes out clean, about 1 hour. Let stand 5 minutes before cutting. Garnish as desired. Serve with salsa. Refrigerate leftovers.Servings: