A custard is a sweetened, milk-based dessert made with eggs and often flavoured with vanilla. Thin, or pouring, custards such as crème anglaise are cooked on the stovetop over low heat, and stirred continuously to prevent lumps from forming. They must be cooked with vigilance or they will curdle. Other custards are made with a wine base, such as zabaglione or sabayon, while others are thickened with flour, usually cornflour. Baked custards are cooked in a bain-marie or water bath so the mixture cooks gently and doesn’t bubble.