A bain-marie is a double boiler or water bath used to heat delicate egg-based sauces such as Hollandaise to help prevent the sauce from splitting due to too high a temperature and for melting chocolate. You can make one using a glass bowl over a pan of gently simmering water. A bain-marie can also be used in making desserts such as set custards and pates and terrines that are baked in the oven and require gentle cooking. A bain-marie can also be used for keeping food warm. In commercial kitchens, a bain-marie can be electrically heated with an element and used to keep soups and sauces hot and ready to serve.