Preheat oven to 400ºF. Cut the squash in half lengthwise and remove the seeds. Drizzle with oil and sprinkle with salt and pepper. Place on a baking sheet, cut-side down, and roast for 40 minutes or until the squash is golden brown and cooked through. Turn off the heat and leave the squash in the warm oven as you finish the soup.

Place the sausage in a soup pot over medium-high heat. Cook, turning occasionally, for 12–15 minutes until completely browned and cooked through. Transfer to a paper towel-lined plate. Drain off all but 1 tablespoon fat in the soup pot and turn the heat back to medium-high.

Add the diced onion to the soup pot and cook for 5 minutes. Add the diced bell pepper and celery to the pot and cook an additional 7–8 minutes until just beginning to soften. Add the garlic and cook for 1 minute more—season all over with salt and pepper.

Melt the butter into the aromatics. Once bubbly, add the dry thyme and crushed red pepper and toss to coat the aromatics with the spices for 1 minute.

Pour in the stock or water along with the diced tomatoes and bring to a boil. Add the sausage back to the pot and simmer for 30–40 minutes—taste and season to your preferences.

Bring the soup back to a boil. Add the tortellini and cook for 5 minutes until cooked through. Turn off the heat and stir in the minced parsley.

As the tortellini cooks, shred the spaghetti squash. Divide the cooked squash between bowls. Ladle the hot soup on top. Enjoy!