1. Heat the olive oil in a large pot or Dutch oven over medium heat.

2. Add the Italian sausage and cook until browned, breaking it into crumbles as it cooks.

3. Stir in the diced onion and cook until softened.

4. Add the garlic and cook for about 30 seconds until fragrant.

5. Stir in the tomato paste and cook for 1 minute.

6. Add the crushed tomatoes, chicken broth, Italian seasoning, red pepper flakes, salt, and black pepper.

7. Bring the soup to a gentle simmer and cook for 10 minutes.

8. Reduce the heat and stir in the heavy cream.

9. Add the cheese tortellini and cook until tender according to package directions.

10. Stir in the baby spinach and let it wilt.

11. Add the Parmesan cheese and stir until melted into the broth.

12. Finish with chopped basil or parsley and serve hot.