Transform & Preserve

Custard Making

Cook eggs and dairy gently to a silky, spoon-coating set

Custard making thickens a mixture of eggs and dairy with gentle, patient heat until it coats a spoon, the basis of crème anglaise, pastry cream, and flan. The danger is overheating into scrambled eggs. Cook low and stir constantly, pulling it the moment it thickens.

Custard making is the gentle art of thickening a mixture of eggs and dairy with patient, controlled heat until it sets to a silky, spoon-coating richness. It underpins crème anglaise, pastry cream, ice cream bases, flan, and quiche. The challenge is the narrow window between perfectly thickened and curdled into sweet scrambled eggs — eggs set just above the temperature where custard becomes lush, so low heat, constant stirring, and a watchful eye (or a thermometer) are everything. Stirred custards thicken on the stovetop; baked custards set gently in a water bath in the oven.

Difficulty: Advanced

Types & varieties

Crème anglaise

A thin pourable stirred custard of yolks, milk/cream, and sugar — the classic dessert sauce and ice-cream base.

Pastry cream

A thick, pipeable custard set with cornstarch so it can boil; for éclairs and tarts.

Baked custard (flan/crème caramel)

Eggs and dairy baked in a water bath until just set.

Quiche / savory custard

Eggs and cream baked into a tender savory set in a crust.

How to do it

1
Warm the dairy
Heat the milk or cream (often with vanilla or other aromatics) until steaming but not boiling.
2
Whisk the eggs and sugar
Beat yolks (and any starch) with sugar until pale and smooth.
3
Temper the eggs
Slowly whisk the hot dairy into the eggs to warm them gradually without scrambling.
4
Cook gently
Return everything to low heat and stir constantly, scraping the bottom, until it thickens.
5
Test the nappe
Pull it the moment it coats the spoon's back and a finger leaves a clear line — that's set, not scrambled.
6
Strain and cool
Strain through a sieve to catch any stray curds, then cool with the surface covered to prevent a skin.

The science

Egg proteins unfold and link together as they heat, building the network that thickens custard. That network sets into silkiness in a narrow band of temperature; push just past it and the proteins bond too tightly, squeezing out liquid and scrambling. Sugar raises the set point and buffers the eggs, giving a little more grace. Starch (in pastry cream) changes the rules entirely — it interferes with the proteins, so a starch-set custard can be boiled without curdling and thickens more firmly.

Rescuing and avoiding curdles

Custard is the classic test of patience at the stove.

Keep the heat low and stir constantly, scraping the bottom where it sets first.
Temper the eggs with hot dairy before combining — never dump cold eggs into hot liquid.
Use a thermometer and pull stirred custard at 82–84 °C to be safe.
If it starts to curdle, immediately strain it or blitz with an immersion blender to smooth it out.

Common uses

Crème anglaise as a dessert sauceIce cream basesPastry cream for éclairs, tarts, and cream puffsFlan, crème caramel, and crème brûléeQuiche and savory custardsTrifle and bread pudding

Tips & pitfalls

A heatproof spatula scraping the bottom prevents hot spots and curdling.
Strain every stirred custard for guaranteed silkiness.
Cover the surface with plastic touching it to stop a skin forming.
Bake custards in a water bath so the edges don't set before the center.
Pastry cream can and should reach a boil to cook out the starch.

Good to know

Set temperature: Stirred custard thickens ~80–84 °C (175–185 °F); curdles by ~85+ °C
Heat: Low and gentle, stirring constantly for stirred custards
Doneness (nappe): Coats the back of a spoon; a finger leaves a clean line
Starch helps: Pastry cream's cornstarch lets it safely boil and thicken further
Baked custards: Set in a water bath (bain-marie) for even, gentle heat

Also called

custard · crème anglaise