Finishing Poaching Liquids

Egg yolks are rarely used alone as a thickener for sauces, but are usually combined with cream and added to a liquid that has already been lightly thickened with flour. Blanquette de veau, a white veal stew finished with cream and egg yolks—one of the cornerstones of French home cooking—illustrates the use of egg yolks as a final liaison for poached meats. The blanched pieces of veal are poached in water or white veal stock along with aromatic vegetables and a bouquet garni. When the veal is tender, after 2 to 3 hours, the liquid is strained, thickened into a classic velouté with flour—about 3½ ounces (100 grams) roux to 1 quart (1 liter) poaching liquid—and then finished with the cream and egg yolk liaison. Recipes vary, but an egg yolk liaison is usually made by combining each yolk with 3 to 4 tablespoons (45 to 60 milliliters) heavy cream, then using 3 to 4 egg yolks’ worth of this mixture to thicken 1 quart (1 liter) velouté. After the liaison has been added to the velouté, the sauce is gently stirred until it naps the back of a spoon. The stability of the egg yolks will depend on the proportion of flour in the velouté, but most recipes do not risk curdling and warn against letting the sauce boil.