Heat the olive oil in a large pot or Dutch oven over medium heat.
Add the onion, carrots, and celery. Cook until softened, about 5 to 7 minutes.
Add the garlic and cook for 1 minute more until fragrant.
Pour in the vegetable broth and diced tomatoes (with their juice). Add the rinsed beans, Italian seasoning, salt, and pepper. Bring the mixture to a boil.
Reduce the heat and simmer for 10 minutes to allow the vegetables to cook through.
Stir in the refrigerated tortellini. Cook according to package directions, usually about 3 to 5 minutes, until the tortellini float and are cooked.
Reduce the heat to low. Stir in the heavy cream and Parmesan cheese until the soup is creamy. Do not boil after adding the cream.
Stir in the fresh spinach until it wilts, about 1 minute.
Serve immediately.
Notes
For a thicker soup, mash about 1/4 cup of the cannellini beans against the side of the pot before adding the broth.
You can substitute frozen tortellini, but adjust the cooking time as needed.
Use chicken broth instead of vegetable broth for a non-vegetarian version.