In a large skillet, heat the oil over medium heat. Add the onion, salt and several grinds of pepper, and cook for 2 to 3 minutes. Add the butternut squash and cook for 6 to 8 minutes.

Add the garlic, rosemary, and the rice. Stir and let cook for about 1 minute then add the wine. Stir and cook for 1 to 3 minutes, or until the wine cooks down.

Add the broth, 3/4 cup at a time, and stir continuously to allow each addition of broth to be absorbed before adding the next. Cook until the butternut squash is tender, and the risotto is soft and creamy. Season to taste.

Garnish with parsley or sage leaves and serve with grated cheese, if desired.