In a large pot, heat a swirl of olive oil over medium heat.
Add the diced onion and cook until translucent, about 4-5 minutes.
Incorporate minced garlic and sauté for an additional minute until fragrant.
Add carrots and celery, cooking for about 5-7 minutes until softened.
Pour in the broth, followed by the diced tomatoes and dried herbs.
Bring the soup to a gentle boil, then reduce the heat to a simmer.
Add the tortellini and cook according to package directions, usually about 5-7 minutes.
In the last couple of minutes, stir in the spinach or kale until wilted.
Taste and adjust seasoning with salt and pepper as desired.
Serve hot, garnished with grated Parmesan or fresh herbs if desired.