A bain-marie, a type of heated bath used in cooking to heat materials gently and gradually to fixed temperatures, or to keep materials warm over a period of time. A bain-marie can also be used to melt ingredients for cooking.
Chocolate can be melted in a bain-marie to avoid splitting and caking onto the pot. Special dessert bains-marie have a thermally insulated container and are used as a chocolate fondue.
Cheesecake is often baked in a bain-marie to prevent the top from cracking in the centre.
Custard may be cooked in a bain-marie to keep a crust from forming on the outside of the custard before the interior is fully cooked.
Classic warm sauces, such as Hollandaise and beurre blanc, requiring heat to emulsify the mixture but not enough to curdle or "split" the sauce, are often cooked using a bain-marie.
Thickening of condensed milk, such as in confection-making, is done easily in a bain-marie.
Bains-marie can be used in place of chafing dishes for keeping foods warm for long periods of time, where stovetops or hot plates are inconvenient or too powerful.