Bain-marie

A bain-marie is a container of hot water that holds a second container of food. The water keeps the food at a gentle, even heat that cannot go above the boiling point of water. Cooks use it in the oven for baked custards and cheesecakes, and on the stove to melt chocolate or make egg sauces such as hollandaise.

How to do it

In the oven:

1. Put your filled dish, ramekins or wrapped springform pan into a larger roasting pan.
2. Set the pan on the oven rack, then pour hot water from a kettle into the outer pan until it comes halfway up the sides of the dish.
3. Bake as the recipe says, usually around 150 to 160°C (300 to 325°F).
4. Lift the dishes out of the water as soon as they come out of the oven so they stop cooking.

On the stove:

1. Bring 3 to 5 cm (1 to 2 in) of water to a bare simmer in a saucepan.
2. Set a heatproof bowl on top so it sits snugly but does not touch the water.
3. Stir the food in the bowl until it melts or thickens.

Why it works

Water spreads heat evenly and gently. The edges of a custard sitting in water cook at nearly the same speed as the middle, so the custard sets smooth instead of turning rubbery or cracking. Over the stove, steam gives soft heat that melts chocolate without scorching it.

Common mistakes

• Pouring water into the pan before it is in the oven. It is heavy and easy to spill.
• Letting water or steam drip into melting chocolate. A few drops can make it seize.
• Letting the water boil hard under an egg sauce. The eggs scramble.
• Skipping the foil around a springform pan. Water seeps in and makes the crust soggy.

In recipes

"Bake in a water bath" and "set over a pan of simmering water" both mean a bain-marie. A double boiler is a pair of nesting pots made for the stove version.

Where it comes from

The name is French for "Mary's bath". It is often linked to Mary the Jewess, an early alchemist, though the story is uncertain.