Ingredient

Choux pastry

Choux is the strangest thing in a baking repertoire: a paste cooked on the hob, beaten with eggs, then baked, where the whole structure is built by steam blowing a hollow in the middle. It is also considerably easier than its reputation, provided you get the egg right.

How it works

Water and butter are brought to the boil, flour is beaten in, and the paste is cooked briefly on the hob. That cooking gelatinises the starch, so the paste can hold a great deal of liquid — which is what lets it take the eggs.

In the oven, the water in the paste turns to steam. The steam has nowhere to go, so it inflates the bun from the inside while the egg and starch set around it into a shell. That is why choux is hollow: the hole is where the steam was.

It follows that anything which lets the steam out early — opening the oven, underbaking, a paste too slack to hold its shape — gives a flat bun. The structure has to set before the steam escapes.

The method

1. Bring water, butter and a pinch of salt to a full rolling boil. The butter must be fully melted before it boils, or the proportions shift as water evaporates.
2. Tip in all the flour at once and beat hard off the heat until it comes together in a ball.
3. Return it to a medium heat and beat for a minute or two, until a floury film forms on the base of the pan and the paste pulls cleanly away from the sides.
4. Take it off and let it cool for five minutes. Adding egg to a paste that is too hot scrambles it.
5. Beat in the eggs a little at a time. This is the step that decides everything — see below.
6. Pipe onto a lined tray and bake hot at first to generate steam, then lower the heat to dry the shells out.
7. When they look done, pierce each one and return them to the turned-off oven for ten minutes to dry the inside. This is what prevents a soggy middle.

Judging the egg

The paste is ready when it falls from a spoon in a thick, glossy V that breaks off rather than running. Some recipes describe a ribbon; a V is more reliable to see. Drawing a line through it with a spatula should leave a channel that closes slowly.

This is why recipes give egg quantities as a range, or by weight. Eggs vary and so does how much moisture your paste lost on the hob. Beat in most of the egg, then add the rest a teaspoon at a time and stop the moment it is right.

Too little egg gives a stiff paste and a dense, cracked bun that does not rise. Too much and it spreads flat on the tray and never recovers. Too little is by far the more recoverable error, so err that way and add more.

Why buns collapse

• The oven was opened early. The shell had not set, the steam left, the bun fell. Do not open it for the first two-thirds of the bake.
• Underbaked. A pale bun is a soft bun and it will sink on the tray. Bake to a genuine deep gold — it always looks darker than feels comfortable.
• Too much egg. The paste could not hold its shape and spread before the heat caught it.
• Not dried out. Trapped steam condenses inside and softens the shell from within. Pierce and return to a cooling oven.
• Filled too early. A warm shell filled with cream goes soggy in minutes. Cool completely, fill as late as possible.

Common questions