Heat oven to 350'F. Spray 2-casserole with vegetable cooking spray. Cook macaroni according to package directions; drain. In casserole, combine macaroni, broccoli, SPAM, and red pepper. In small saucepan, stir together milk, cornstarch, and pepper until cornstarch is dissolved. Bring to a boil, stirring constantly, until thickened. Reduce heat to low. Add cheese; stir until melted. Stir sauce into SPAM mixture. combine bread crumbs and margarine; sprinkle on top of casserole. Bake 40 minutes or until thoroughly heated.