Heat oven to 350°F. Spray 2-quart casserole with nonstick cooking spray. Cook macaroni according to package directions; drain. In prepared casserole, combine macaroni, broccoli, SPAM® and bell pepper. In small saucepan, stir together milk, cornstarch and black 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.