Preparation. Preheat oven to 450°. Combine first 3 ingredients; stir well. Dip the zucchini slices in egg whites; dredge in breadcrumb mixture. Place zucchini in a single layer on a baking sheet coated with cooking spray. Bake at 450° for 20 minutes. Turn zucchini over; bake an additional 15 minutes or until outside is crispy and browned.