Preheat oven to 375. Prepare a 2-quart casserole dish with cooking spray; set aside. In a saucepan, melt margarine over medium-high heat; sprinkle with flour. Cook, whisking quickly and constantly, for two minutes. Whisk in milk and parmesan cheese. Cook stirring constantly for another two minutes until thickened. Remove from heat. Add noodles, turkey, onions, bell peppers, and mustard to saucepan; toss to mix well. Spoon mixture into prepared dish and sprinkle with bread crumbs. Bake for 20 minutes, or until browned and bubbly.