Choux is cooked twice and the first cook is the one people rush

Everything below about making choux paste comes from what actually happens rather than from what is supposed to.

The two cooks

Choux begins by bringing water, butter and salt to a boil, then beating in flour and cooking the paste on the hob. That first cook gelatinises the starch and drives off water, which is what lets the paste absorb a large quantity of egg later. The second cook is in the oven, where the water still in the paste turns to steam and inflates each bun into a hollow shell.

The egg proteins then set around that expanded shape and hold it once the steam escapes. Rushing the first cook leaves too much water in the paste, so it takes less egg and produces flat, dense buns.

Judging the hob stage

Beat the flour in off the heat first to avoid lumps, then return the pan and stir continuously for two to three minutes. The paste is ready when it comes away cleanly from the sides and leaves a thin dried film on the base of the pan. It should also look slightly glossy and smell faintly of cooked flour rather than raw.

A non-stick pan makes the film test difficult, so use a heavy stainless steel pan if you have one. Undercooking here is by far the most common fault in home choux.

Adding the eggs

Cool the paste for four or five minutes so the eggs do not scramble, then add them a little at a time. The paste will look broken and slippery after each addition and will come back together with beating, which is normal. Stop adding when the paste falls from the spoon in a thick ribbon that leaves a V hanging from the edge.

Recipes give an egg count but the correct amount depends on how much water you drove off, so judge by texture. Too little egg gives a stiff paste that will not expand; too much gives a slack one that spreads and will not hold shape.

Piping and shaping

Pipe onto a lightly greased or parchment-lined tray, holding the bag vertically and lifting sharply to break the flow. Flatten any peak with a wet fingertip, since a point will burn before the rest of the bun has coloured.

Space the buns generously, as they typically double or more and will fuse if crowded. A light spray of water on the tray creates a little steam in the early minutes and helps expansion.

Consistent size matters more than perfect shape, since uneven buns bake at different rates on one tray.

Oven temperature strategy

A common approach starts hot, around 200 to 220C, to generate steam quickly and drive the expansion. After the buns have risen and set, usually fifteen to twenty minutes in, the temperature drops to around 170 to 180C. That lower stage dries the shell so it stays crisp rather than softening as it cools.

In the tin, do not open the door during the first stage, since a collapse at that point is permanent. The buns are done when they are a deep golden brown all over, including the sides, and feel light for their size.

Proving times are written for a warm kitchen, and yours may not be one.

Drying the shells

Even a well baked bun holds moist, uncooked strands inside, and that moisture will soften the shell as it cools. Pierce each bun in the base or side with a skewer and return them to a switched-off warm oven for ten minutes.

The vented steam escapes rather than condensing, and the interior dries into a light, papery web. Cool on a rack rather than the tray, so the base does not sit in its own moisture. Fill as close to serving as possible, because a filled bun softens within an hour or two whatever you do.

The takeaway

Dry the paste properly on the hob, judge the egg by texture, and vent the shells before they cool.

Bake it badly once on purpose. The failure teaches more than the photograph.