In a large pot over medium heat, heat the extra virgin olive oil. Saute onion, celery and carrot stirring occasionally until the vegetables begin to soften and become fragrant, about 10 minutes. Add the garlic, and cook an additional minute or two.
Add the stock and water, and raise the heat to bring to a boil. Reduce the heat to medium and add the Tortelloni, cooking them in the soup according to package directions.
Add the parsley and season with salt and pepper.