Preheat the oven to 450°. Rinse the cauliflower. Separate the cauliflower into florets. Place the cauliflower into a large mixing bowl. Add the olive oil and garlic. Add salt and pepper to taste. Toss to coat. Spray a large baking dish with non-stick cooking spray. Pour the cauliflower into the baking dish and arrange in a single layer. Bake for 25 minutes at 450°, stirring halfway through. Remove from the oven and sprinkle the Parmesan cheese and parsley over the cauliflower. Return to the oven and bake for an additional 5 minutes.