1. In a large pot or Dutch oven, bring canned tomatoes, chicken broth, Italian seasoning and frozen vegetables to a boil over medium-high heat.
2. Reduce heat and simmer for 10 minutes.
3. Add in tortellini and spinach and return to a boil, then reduce heat and simmer for 10 minutes.
4. Season with salt and pepper to taste. (I have not added specific amounts here because it will depend on the type of canned tomatoes and chicken broth that you are using. If you're using low-sodium varieties of both, then you will want to add approximately 1/2 tsp. of salt or more to taste).
Garnish with freshly grated Parmesan cheese if desired.
Store leftovers in refrigerator to up to three days.
The tortellini will soak up a lot of the liquid overnight and you will have to add in some chicken or vegetable stock when you heat it up.