To make pate a choux you will need:
All purpose flour
A mixer electric or manual.
Step 1: Mise En Place!
4.5oz all purpose flour
1/4 teaspoon of salt
Place the butter, water, and salt into a sauce pan that will give you enough room to stir. Turn your range up to medium heat to melt the butter.
Step 2: Dough!
You are trying to achieve a dry-ish dough here, while also cooking the flour. Choux dough is a strange animal and can be a bit finicky to work with so give it time, about 5 mins. You want a thin film of cooked dough to form on the bottom of the pan and for most of the dough you are stirring to come together in a ball. It will have steam coming from it, so be careful not to burn your hands.
Turn off your range and place the dough into the bowl of your mixer or a clean bowl to be mixed by a hand mixer. Use a paddle attachment and begin beating the dough. Let your mixer go for 5 mins. You want to dough to cool down enough so that when you add the eggs, the proteins in the eggs wont seize.
You can clean the pot or do a little dance. Whatever to pass the time. Touch the dough periodically. It should be warm when its ready, not hot. You should be able to hold it comfortably in your hand.
Step 3: Batter Up
The mix will look odd at first, but as you keep mixing you will notice a batter beginning to form. The batter for choux is smooth, slick and thick.
A word on eggs and flour: when making anything where you are adding a liquid to flour, take a few things into consideration. Flour can be more dry or moist depending on how it is stored, from where it is shipped, how old it is, or the weather in your area. When making bread, you might find you need less water than normal or maybe more on any given day. That is because it may have been dryer than usual, or very wet in your area. I find that using air tight containers make for a drier flour, but I can count on more consistency. The same is true for this batter. Choux sometimes will take less eggs, but that is usually in large batch instances. Here I have given you a base egg amount and from there you can add more eggs but not less. The reason you're adding eggs to this is because the eggs are your leavening agent in this dough. The water in the whites and dough provide steam which creates the defining air pockets in the finished product. The protein in the flour and yolks are what provide the structure so that the dough, when baked, doesn't just fall apart. You are developing gluten while you beat the flour and incorporating air, which is vital. The eggs, when the right amount are added, also add to the shine of the finished product and wont require you to egg wash them before baking.
Watch your choux, it should begin to look smooth like cake batter and stick to the sides of the bowl. Stop the mixer and scrape down the sides before adding the last egg. When the last egg has been combined, turn off your mixer and feel your dough. It should be tacky but no longer warm. If your dough breaks and looks jagged when you work some between your fingers, scrape down your bowl and add one more egg. Mix until incorporated. It will look shiny and still be tacky but should have a bit more stretch and flow to it.
Step 4: Possibilities
You have successfully created Choux batter and are now ready to make whatever your heart desires. Maybe you will make delicious savory gougeres. Perhaps you will take on the sweet and delicate Paris-Brest. Or if you're feeling daring make a few Pate a Choux Swans to impress the parents at the next PTA.
A note on keeping Choux dough. It freezes well, as long as it is in the form of what you're going to bake before you freeze it. You cannot thaw the dough and re pipe or scoop it. It just doesn't work well, so use it up and have a bit of fun. Chox has endless possibilities.