Bring first 3 ingredients to a boil in a Dutch oven over medium-high heat.
Add spinach, stewed tomatoes, and garlic, and return mixture to a boil.
Stir in tortellini, and cook for 5 minutes. Sprinkle each serving evenly with shredded Parmesan cheese.
Note: For testing purposes only, we used Knorr Vegetable Bouillon Cubes.