Cook the sausage: Heat your soup pot over medium heat. Remove the sausage from its casing and crumble it into the pot. Cook until browned and fully cooked through, about 6-8 minutes. Use a slotted spoon to remove the sausage and set it aside.

Sauté the vegetables: In the same pot, add the chopped onion and garlic. Sauté for 2-3 minutes until softened and fragrant.

Add broth and seasonings: Pour in the chicken broth and bring the mixture to a simmer. Stir in the Italian seasoning, red pepper flakes (if using), and salt and pepper to taste.

Add tortellini: Stir in the tortellini and cook for 5-7 minutes, or until the pasta is tender and cooked through.

Add cream and spinach: Pour in the heavy cream and bring the soup back to a simmer. Stir in the chopped spinach and cook for another 3-4 minutes, until the spinach is wilted and the soup is creamy.

Return sausage to pot: Add the cooked sausage back into the pot and stir to combine. Let the soup simmer for an additional 2-3 minutes to ensure everything is heated through.

Serve and garnish: Ladle the soup into bowls and garnish with grated Parmesan cheese, if desired. Serve hot and enjoy!