1. Preheat oven to 400 degrees F.

2. Cut off the very top and bottom of each squash to create a flat base on each side.

3. Slice the squash in 1/2, scrape out seeds to create individual bowls for the stuffing.

4. Drizzle each squash 1/2 with olive oil, salt, and pepper.

5. Roast for 40-50 minutes, or until fork tender.

6. While squash is roasting, in a large skillet over medium heat, heat oil and add onion, celery, salt, pepper, and rosemary. Cook until the onions begin to soften.

7. Add garlic and sausage, cook until sausage is browned on all sides.

8. Add apple and cook until slightly softened. Finally mix in bread crumbs and Parmesan cheese just until incorporated. Remove from heat.

9. Once squash has finished roasting (when you can easily pierce with a fork), remove from oven and fill each with prepared stuffing mix.

10. Return to oven for 20 minutes, add a sprinkle of Parmesan cheese to each top for the final 5 minutes.