Always preheat the oven before beginning to make the choux pastry, as it needs to be cooked as soon as it is shaped or piped. Likewise, prepare your equipment before you start. Line the baking tray with baking paper. If piping the dough, fit a large plain nozzle to the piping (icing) bag.
Add the flour to the boiling mixture in one go, then immediately beat the mixture with a wooden spoon to prevent lumps forming. Stop beating as soon as the soft dough comes away from the sides of the pan and remove from the heat.
Always allow the hot mixture to cool for 2–3 minutes before adding eggs or they can start to cook.
The dough is ready when it is smooth and glossy. It should be piped or shaped while it is still warm.