Preheat oven to 350°. Cook spaghetti according to package directions for al dente; drain., In a large skillet, cook beef, onion and green pepper over medium heat 5-7 minutes or until beef is no longer pink, breaking up beef into crumbles; drain. Stir in tomatoes, tomato paste, seasonings and sugar., In a large bowl, whisk egg whites, melted butter and Parmesan cheese until blended. Add spaghetti and toss to coat. Press spaghetti mixture onto bottom and up sides of a greased 9-in. deep-dish pie plate, forming a crust. Spread cottage cheese onto bottom; top with beef mixture. , Bake, uncovered, 20 minutes. Sprinkle with mozzarella cheese. Bake until heated through and cheese is melted, 5-10 minutes longer. Let stand 5 minutes before serving.