Preheat oven to 350°. In a 6-qt. stockpot, cook macaroni according to package directions for al dente; drain and return to pot.
Meanwhile, in a medium saucepan, melt butter over medium heat. Stir in flour, salt and pepper until smooth; gradually whisk in milk. Bring to a boil, stirring constantly; cook and stir until thickened, 1-2 minutes. Stir in cheeses until blended. Stir in dressing.
Add chicken and sauce to macaroni, tossing to combine. Transfer to a greased 13x9-in. baking dish.
Toss bread crumbs with melted butter; sprinkle over macaroni. Top with bacon. Bake, uncovered, 30-35 minutes or until topping is golden brown. Sprinkle with parsley.
Source:
tasteofhome.com