Cabillaud à la Bordelaise

Wash and dry the fish and marinate it: season the steaks with salt and pepper and put them in a shallow dish. Sprinkle with the sliced onion, parsley, thyme and bay leaf. Pour the wine over the fish, then the oil. Marinate for 45 minutes.

Meanwhile, prepare the tomato and onion purée: heat the oil in a frying pan, add the onions and cook over a low fire, stirring, until soft but not bro