Custard refers to a number of culinary preparations involving whipped and cooked milk, sugar and egg yolk mixtures. Custards are typically very rich and thick and have many uses in desserts. Custard bases may also be used for quiches and other savoury foods. As a dessert, it is made from a combination of milk or cream, egg yolks, sugar, and vanilla. Sometimes flour, corn starch, or gelatin is added.
Custard is usually cooked in a double boiler (bain-marie) or microwave, or heated very gently in a saucepan on a stove, though custard can also be steamed, baked in the oven with or without a hot water bath, or even cooked in a pressure cooker. Custard preparation is a delicate operation, because a temperature increase of 5–10 °F (3-6 °C) leads to overcooking and curdling. Generally, a fully-cooked custard should not exceed 80°C; it begins setting at 70°C. A water bath slows heat transfer and makes it easier to remove the custard from the oven before it curdles.
Depending on how much egg or thickener is used, custard may vary in consistency from a thin pouring sauce (crème anglaise), to a thick pastry cream used to fill éclairs.
Custard is an important part of dessert recipes from many countries.
Custard was known in English cuisine at least as early as the fourteenth century. Recipes for custards baked in pastry (custard tarts) appear, under titles such as Crustardes of flessh and Crustade, in The Forme of Cury and Harleian MSS 279 and 4016. These recipes include solid ingredients such as meat, fish, and fruit, which are baked in the custard. Meanwhile, recipes for stirred custards cooked in pots appear in the same Harleian MSS as Creme Boylede and Creme boiled.