2-4 ounces reduced-fat feta, or goat, cheese, crumbled
Dip eggplant slices in egg whites and coat with combined bread crumbs and Parmesan cheese. Spray large skillet with cooking spray and heat over medium heat until hot. Cook eggplant until browned on the bottom, about 10 minutes; spray tops of slices with cooking spray and turn. Cook until eggplant is tender and browned on other side, about 10 minutes longer.
Arrange eggplant in baking pan; top each slice with a slice of polenta and tomato. Sprinkle tomatoes with salt and pepper; sprinkle stack with feta cheese.
Bake at 450 degrees F. until tomatoes are hot and cheese lightly browned, about 10 minutes.