2 tablespoons grated Parmesan cheese, plus more for serving
2 large eggs, beaten
Salt and freshly ground pepper
In a saucepan, combine the stock and garlic and bring to a boil. Add the carrot and celery, cover and cook over moderately high heat until the celery is crisp-tender, about 4 minutes. Add the spinach, parsley and 2 tablespoons of Parmesan and simmer for 2 minutes.
Beat the eggs in a bowl and pour them into the soup. Cook over moderately low heat for 30 seconds, gently stirring with a fork until threads appear. Season with salt and pepper. Ladle the soup into bowls; serve with Parmesan cheese.