Heat the olive oil in a large Dutch oven or stockpot over medium heat. Add the chopped onion and cook, stirring occasionally, until softened and translucent, about 5-7 minutes.

Stir in the minced garlic and red pepper flakes (if using). Cook for about 1 minute more, until fragrant.

Pour in the crushed tomatoes and vegetable broth. Add the dried oregano, dried basil, salt, and pepper. Stir everything together and bring the soup to a simmer.

Once simmering, reduce the heat to low, cover, and let it gently simmer for 15 minutes to allow the flavors to meld together.

Add the refrigerated tortellini to the pot. Increase the heat to medium and cook according to package directions, typically 3-5 minutes, or until the tortellini are tender and float to the top.

Reduce the heat to low. Stir in the heavy cream and grated Parmesan cheese until the cheese is melted. Add the fresh spinach and stir until it has just wilted, about 1-2 minutes. Do not let the soup boil after adding the cream.

Taste the soup and adjust seasoning with more salt and pepper if needed. Ladle into bowls and serve immediately, garnished with extra Parmesan cheese and fresh basil, if desired.