Preheat the broiler to high. Cut the polenta into 1/2-inch slices. Place the slices on a baking sheet coated with cooking spray. Broil 4 minutes or until lightly browned. Turn the polenta slices over; sprinkle each with 1 tablespoon Parmesan. Broil 3 minutes or until lightly browned. Cool slightly, and cut each slice into 4 wedges.