Preheat the oven to 425 degrees. Spray a baking sheet with cooking spray.
Slice the squash into 1/4 inch slices. Toss them with the olive oil and arrange on the baking sheet so they are touching but don't overlap.
Sprinkle the squash with the salt, garlic powder, and pepper. Spread Parmesan cheese on top of each squash round.
Bake for 15-20 minutes.