Place the squash on its side and slice off both ends using a sharp knife. Use a peeler to remove the skin. Cut the neck of the squash off and remove the seeds and pulp. Slice it into rings and then into cubes.
Preheat oven to 425 degrees F. Place prepped squash, olive oil, rosemary, salt, and prepper on a baking sheet. Toss to coat.
Roast for 15 minutes. Toss squash and continue to roast for 5 more minutes. Sprinkle with parmesan cheese and roast for 3-5 more minutes until cheese is melted.