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 cooks' guild regulations allowed for this movement. During the 16th and 17th centuries, French cuisine assimilated many new food items from the New World. Although they were slow to be adopted, records of banquets show Catherine de' Medici (1519–1589?) serving sixty-six turkeys at one dinner. The dish called cassoulet has its roots in the New World discovery of haricot beans, which are central to the dish's creation, but had not existed outside of the New World until its exploration by Christopher Columbus. Haute cuisine (, "high cuisine") has foundations during the 17th century with a chef named La Varenne. As