Add butter to a large pot over medium heat. Once melted, add the onion and garlic and cook, stirring occasionally, 5 minutes.
Stir in the flour and cook for another minute.
Add the vegetable broth, diced tomatoes, tomato sauce, Italian seasoning, and dried basil. Season with salt and pepper.
Bring mixture to a gentle boil and then add the tortellini. Cook for 4-6 minutes, until tortellini are tender.
Remove from heat and stir in spinach, parmesan cheese, and cream.
Add chopped basil, a sprinkle of parmesan, and enjoy!