HEAT oven to 350°F.
MELT margarine in large saucepan on medium heat. Whisk in flour; cook 1 min., stirring constantly. Gradually stir in milk; cook and stir 3 to 5 min. or until thickened. Add 1-1/2 cups cheddar and Parmesan; cook and stir 1 min. or until cheddar is melted.
ADD macaroni; stir to evenly coat. Spoon into 1.5-L casserole dish sprayed with cooking spray. Top with remaining Cheddar and bread crumbs.
BAKE 20 min. or until lightly browned and heated through.
serving size = 1-1/4 cups (300 mL)