Heat 2 tablespoons olive oil in a large pot or Dutch oven over medium-high heat and add onion and carrot.
Sauté for 10-12 minutes, stirring frequently, until onions are translucent. Season generously with salt and pepper.
Add minced garlic and cook for 1-2 minutes, or until fragrant, then add ⅓ cup basil, chicken stock and canned tomatoes, then add red pepper flakes.
Stir everything together and bring to a boil, then reduce heat to low and simmer for 20 minutes, or until thickened. Taste and adjust seasoning, if necessary.
Add tortellini to soup and continue to let simmer for another 15-20 minutes, or until pasta is al dente.
Pour in heavy cream and parmesan cheese, if using, and stir together.
Transfer to serving bowls and serve hot, garnished with more cheese and fresh basil. Enjoy!