Preheat oven to 400°F.
Prepare a 13x9 baking sheet by spraying with vegetable spray - set aside.
Peel eggplant and cut into 1⁄4 inch slices.
In a shallow dish, beat egg whites and 4 tbsps water until foamy .
Dip eggplant slices into egg whites, then into fat-free Parmesan cheese, pressing cheese into eggplant .
Place eggplant on the prepared baking sheet and sprinkle with garlic powder to taste.
Spray vegetable cooking spray over eggplant slices.
Bake 20 minutes & turn eggplant over.
Bake an additional 10 minutes.
Cover with 1 cup of marinara sauce.
Return to the over and bake for an additional 20 minutes, or until eggplant is piping hot and sauce is bubbly.