Baked Custard

Our answer

With a baked egg custard the mixture sets as the proteins in the egg coagulate. When this happens the protein strands that are usually curled up start to unwind and stick to each other, causing the liquid they are in to thicken. However if the proteins are overcooked, either by using a temperature that is too high or just cooking for too long, then the proteins will come together so tightly that they will start to squeeze out water and this causes the weeping in an egg custard (or the scientific term for this is syneresis).

Pyrex dishes are fine for egg custards but they do retain heat quite well and the custard will continue to cook in this residual heat as it stands, which may be one reason why the leftover egg custard weeps. Also the direct heat of an oven can be quite harsh, which may also be another of the causes of the weeping.

We would suggest that the custard is cooked in a water bath, or bain marie, instead of directly on the oven shelf. As water can only heat up to 100c the water bath will cook the custard very gently and more evenly. As soon as the custard is ready (it should only just be set) then take it out of the water bath and let it cool slightly before serving. The Pyrex dish should not heat up as much if it is in a water bath so the risk of overcooking as the dish cools is also reduced. If you have not baked the custard in a water bath before then you may find that the cooking time is longer than for your original recipe.

3 eggs to 1 pint (600ml/2 1/2 cups) of milk is also slightly low and you may like to try the custard with 4 eggs, unless your eggs are very large. You may also like to try Nigella's Baked Egg Custard recipe from Kitchen (p260).