Heat oven to 375°F. Spray 12x8- or 13x9-inch (3-quart) glass baking dish with cooking spray. Place stuffing cubes in dish; stir in gravy.
Top with onion, pork chops and apple. Cover with foil.
Bake 40 minutes. Uncover; bake 10 to 15 minutes longer or until pork is no longer pink in center.