In a large pot, heat a drizzle of olive oil over medium heat. Add the sweet Italian sausage, breaking it into smaller pieces as it cooks. Season with kosher salt and pepper. Brown for about 6-8 minutes until fully cooked.

Once the sausage is cooked, add in the diced sweet onion, minced garlic, and cubed butternut squash. Stir well and cook for 5-6 minutes, or until the onion is translucent.

Next, stir in the tomato paste, allowing it to cook for a minute to enhance its flavor. Then add fire-roasted diced tomatoes, Parmesan rind, and chicken stock. Bring to a boil, then reduce to a simmer for 15-20 minutes.

Check that the butternut squash is tender with a fork. This should infuse the soup with a rich, comforting taste and sweet flavor.

Stir in heavy cream and choice of kale or spinach, and let cook for another minute. Add the cheese tortellini and cook for approximately 5 minutes until tender.

Taste and adjust seasoning if needed. Ladle into bowls, topping with Parmesan cheese and crushed red pepper flakes if desired. Serve immediately.