I’ve mentioned a few times working with custards baked in water baths like creme caramels or brulees. They aren’t anywhere near as complicated as they seem, but the depth of the water bath is important.
Too shallow a water bath and the custards will bake very fast, giving you only a small window when they are perfectly done. The water may also evaporate entirely, leaving uninsulated custard to bake with too much heat overcooking the edges before the centre is set.
Too deep a bath and your brulees will be in the oven until the cows come home, and you run the risk of water spilling into the custard at any point.
The best level to have the water is about 1/3 of the way up the side of the dish. Another trick is to place the ramekins in a small enough water bath that there isn’t too much surface area of just water, this will stop the water evaporating too fast.
