Cook and drain macaroni as directed on box. Return to saucepan; keep warm.
Meanwhile, heat oven to 375 degrees F. Spray 13x9-inch glass baking dish with cooking spray. In 2-quart saucepan, heat cream, mustard, salt and red pepper to boiling. Reduce heat; stir in Cheddar cheese with wire whisk until smooth. Pour sauce over macaroni. Stir in tomatoes and onions. Pour into baking dish. In small bowl, stir together Parmesan cheese and bread crumbs; stir in oil. Sprinkle over top of macaroni mixture.
Bake 20 to 25 minutes or until edges are bubbly and top is golden brown.