In a large stock pot, cook the sausage over medium heat until sausage is no longer pink. Drain, if desired, and remove sausage from pot. Set aside.
Add butter to pot and let melt over medium heat. Add in onion, carrots, and celery; cook until tender.
Add in garlic and Italian seasoning, cook for about 1 minute more.
Add in flour with the vegetables and mix until all vegetables are lightly coated.
Pour in chicken broth, then add in tomatoes and tomato paste and stir.
Add in heavy cream, tortellini and spinach and bring to a simmer for about 6-7 minutes or until tortellini is cooked and spinach is wilted.
Season with salt and pepper before serving.
Top each bowl with freshly grated Parmesan cheese.
Notes
Spicy Italian sausage is delicious in this recipe if you like a little heat!
The tortellini will soak up a lot of the broth after it sits, so the leftovers won't have much liquid. We recommend making this the same day that you want to eat it to avoid that problem. With your leftovers, you can always add some more chicken broth and/or heavy cream if you want more liquid in it.
This soup is still delicious without the cream. I would add in an extra cup of chicken broth to make up the difference of the liquid in the soup.
You could also substitute kale for the spinach.
If you want to add more vegetables, I love throwing in fresh sliced mushrooms and diced bell peppers in with the onions, carrots, and celery.