2Meanwhile, melt 4 tablespoons butter in a large saucepan. Stir in flour until smooth. Gradually add milk. Bring to a boil; cook and stir for 2 minutes.
3Reduce heat; add cheeses, mustard, salt and pepper. Stir until cheese is melted and sauce is smooth. Drain macaroni; add to the cheese sauce and stir to coat.
4Transfer to a greased shallow 3-quart baking dish. Melt the remaining butter; toss with bread crumbs and parsley. Sprinkle over macaroni. Bake, uncovered, at 400ºF for 15 to 20 minutes or until golden brown.