Chop together, fine, one quarter of an onion, a clove of garlic, a piece of celery as long as your finger, a few bay leaves and just enough parsley. Season with a little oil, salt and pepper, cut up seven or eight tomatoes and put everything over the fire together. Stir it from time to time and when you see the juice condensing into a thin custard strain through a sieve, and it is ready for use.
