In a large pot, heat the EVOO over medium heat.
Add the chopped onion and sauté until translucent and tender, about 4-5 minutes.
Add the minced garlic and sauté for another minute until fragrant.
Stir in the diced tomatoes with their juices.
Add the vegetable or chicken broth to the pot and stir to combine.
Season with dried basil, dried oregano, salt, freshly ground black pepper, and red pepper flakes (if using). Stir well.
Bring the mixture to a boil, then reduce the heat to low and let it simmer for about 10 minutes.
Increase the heat to medium and add the tortellini to the pot.
Cook according to the package instructions until the tortellini are al dente, usually around 4-5 minutes for fresh tortellini or 8-10 minutes for frozen.
Stir in the chopped spinach or kale. Allow it to wilt and cook in the soup for about 2-3 minutes.
Ladle the soup into bowls.
Garnish with grated Parmesan cheese, fresh parsley or basil.
Drizzle with a bit more EVOO for added flavor if desired.