Cook macaroni in boiling salted water according to package directions until barely al dente. Drain. In small saucepan, bring milk to a simmer. Remove from heat. In large saucepan, melt 1/2 cup butter. Blend in flour; cook, stirring, for 1 minute. Gradually stir in milk, whisking constantly, until smooth. Cook over medium heat, stirring constantly, until thickened and mixture comes to a boil; cook and stir 1 minute. Blend in mustard, salt, pepper and cheeses. Stir over low heat until cheese is melted. In large bowl, combine macaroni and sauce. Spoon into buttered 9x13-inch glass baking dish. Combine crumbs with 2 tablespoons melted butter; sprinkle over macaroni. Bake, uncovered, in a preheated 350 F oven until light golden brown and bubbly (35-40 minutes). Serve immediately.

Tip: May be served as an accompaniment to a meat entree. Spoon unbaked macaroni and cheese into individual ramekins. Top with crumbs. Bake as directed for 15-20 minutes.