1. Prepare macaroni according to package directions, omitting salt and butter; drain well.
2. Place milk and next 4 ingredients in a quart jar; cover tightly, and shake vigorously 1 minute. Stir together milk mixture, cheese, spinach, and macaroni.
3. Pour macaroni mixture into a 13- x 9-inch baking dish coated with butter-flavored cooking spray. Sprinkle evenly with breadcrumbs; lightly coat breadcrumbs with cooking spray.
4. Bake at 350° for 30 minutes or until golden brown.
Note: For testing purposes, we used Barilla Plus pasta and Sara Lee Soft & Smooth Whole Grain White Bread.