Filets de Poisson Gratinés, à la Parisienne [Fish Filets Poached in White Wine; Cream and Egg Yolk Sauce]
In the following recipe, the fish poaching liquid is cooked with a flour and butter roux to make a fish velouté. The velouté is then combined with cream and egg yolks to produce a delicious, velvety sauce called a parisienne. Although it uses almost the same elements as the sauce Bercy, because of its cooked roux and its egg yolks, sauce parisienne is far more subtle in taste and texture. It is the basis for all the great fish sauces described later. When the sauce is to be used for a gratin, as in this recipe, the whole dish may be prepared ahead of time, and reheated later. Before the fish is sauced, it may be surrounded with various cooked shellfish as suggested at the end of the recipe. Serve with this a chilled white Burgundy, or an excellent white Graves.