Have your fishmonger prepare the fish fillets and give you the heads and bones. Make a stock by boiling these trimmings, uncovered, for 1 hour with the vegetables and the bouquet garni in 4 pints of water. Salt, pepper. Strain. Put the fillets into a high-sided frying pan or a saucepan. Cover with the stock. Bring to a boil. Turn off the heat. Cover. Poach the fish for 3 minutes. Take the fillets out and drain. Keep warm on the serving dish. Take 1 pint of stock and reduce it by 1/3. Add the cream and the tomato paste. Adjust the seasoning to taste. Remove from the heat, pour the egg yolks one by one into the sauce, whipping thoroughly. Thicken over a low heat without boiling. Fry 1/4 cress leaves in butter. Add to the sauce. Pour the sauce over the fillets. Sprinkle with a little chopped cress.
