Custard is a variety of culinary preparations based on sweetened milk, cheese, or cream cooked with egg or egg yolk to thicken it, and sometimes also flour, corn starch, or gelatin. Depending on the recipe, custard may vary in consistency from a thin pouring sauce to the thick pastry cream used to fill éclairs. The most common custards are used in custard desserts or dessert sauces and typically include sugar and vanilla; however, savory custards are also found, e.g., in quiche.

Cream is a dairy product composed of the higher-fat layer skimmed from the top of milk before homogenization. In un-homogenized milk, the fat, which is less dense, eventually rises to the top. In the industrial production of cream, this process is accelerated by using centrifuges called "separators". In many countries, it is sold in several grades depending on the total butterfat content. It can be dried to a powder for shipment to distant markets, and contains high levels of saturated fat.