Preheat oven to 350°F. Coat a 2-quart square baking dish with nonstick coating; set aside. Cook fusilli as directed on package. Drain and return to pot; keep warm.
While macaroni cooks, melt light butter in a medium saucepan. Add flour and salt; stir for 1 minute. Add milk; stir over medium heat until thickened and bubbly. Remove from heat; stir in cheese until melted.
Toss together macaroni and sauce. Transfer to prepared dish. Sprinkle evenly with breadcrumbs. Bake for 20 minutes or until heated through.