Combine soup, milk, onion and mustard in medium bowl; blend well. Spread sauerkraut in greased 13 x 9 inch pan. Top with uncooked noodles. Spoon soup mixture evenly over top. Top with sausage, then cheese. Combine crumbs and butter in small bowl; sprinkle over top. Cover pan tightly with foil. Bake in preheated 350 degree oven 1 hour or until noodles are tender. Garnish as desired.