Add Broth and Tomatoes: Pour in the vegetable broth and add the diced tomatoes (with their juices). Stir in the Italian seasoning, salt, and black pepper.
Bring to a Boil: Increase the heat and bring the mixture to a boil. Once boiling, reduce the heat to a simmer.
Cook the Tortellini: Add the tortellini to the pot and cook according to package instructions, usually about 3-5 minutes for fresh tortellini or 7-10 minutes for frozen.
Add Spinach: In the last couple of minutes of cooking, stir in the fresh spinach (or kale) and cook until wilted.
Serve: Once everything is cooked through, ladle the soup into bowls and top with grated Parmesan cheese and fresh parsley, if desired.