Hollandaise sauce mayonnaise and Béarnaise, the egg does not coagulate as in a custard; rather, the lecithin in the eggs serves as an emulsifier, allowing the mixture of the normally immiscible butter and lemon juice to form a stable emulsion. To make hollandaise sauce, beaten egg yolks are combined with butter, lemon juice, salt, and water, and heated gently while being mixed. Some cooks use a double boiler in order to control the temperature. Some recipes add melted butter to warmed yolks; others call for unmelted butter and the yolks to be heated together; still others combine warm butter and eggs in
French cuisine these sea mammals were eaten. Artificial freshwater ponds (often called "stews") held carp, pike, tench, bream, eel, and other fish. Poultry was kept in special yards, with pigeon and squab being reserved for the elite. Game was highly prized, but very rare, and included venison, wild boar, hare, rabbit, and birds. Kitchen gardens provided herbs, including some, such as tansy, rue, pennyroyal, and hyssop, which are rarely used today. Spices were treasured and very expensive at that time – they included pepper, cinnamon, cloves, nutmeg, and mace. Some spices used then, but no longer today in French cuisine are cubebs,