Custard is a kind of dessert. Though the amount of subspecies vary, the most basic custard comes from sweetened milk, cheese, or cream cooked with egg or egg yolk for thickening. Some custards come with flour, corn starch, or gelatin. Custards also vary in viscosity, from the thin crème anglaise to the thick crème pâtissière, the latter used to fill éclairs. Some custards are used beyond desserts, as in quiche.