In a large Dutch oven, crumble the Italian turkey sausage and add the chopped onion. Cook over medium heat for about 5-7 minutes, stirring occasionally, until the sausage is no longer pink and starts to brown.

Add minced garlic to the pot and sauté for another minute until fragrant.

Stir in the reduced-sodium chicken broth, water, and diced tomatoes, increasing the heat to bring the mixture to a boil.

Once boiling, add the refrigerated cheese tortellini to the pot and cook for 5-8 minutes, stirring occasionally until the tortellini float and are nearly tender.

Reduce the heat and gently fold in the fresh baby spinach, basil, pepper, and red pepper flakes. Cook for an additional 2-3 minutes until the spinach wilts.

Ladle the Tortellini Soup into warm bowls, and top each serving with shredded Parmesan cheese, if desired.