Brown ground sirloin in butter in skillet, stirring until crumbly; drain. Stir in tomato sauce. Cook noodles according to package directions. Combine cheese, sour cream and vegetables in bowl; mix well. Layer noodles and cottage cheese mixture half at a time in 9x13" baking dish. Pour beef mixture over layers. Bake at 350 F. for 30 minutes. Yield: 8-10 servings.