You can apparently make the choux ahead of time and brush the surface with egg to keep it from forming a crust, but I never do. I make the shells in whatever shape I want, and once they are completely cool, I store them in an airtight container until I'm ready to fill them. I have personally never kept them beyond a few hours, but you can keep them for 3 days this way.
If you do want to make savoury choux buns, you can add a little flavouring to the mixture as you cook it. For example, you could try adding a little cayenne, some paprika or just salt and pepper.
Choux pastry is made for filling. It quite literally has air pockets in the middle which are perfect for filling with cream or creme patissiere. Or perhaps ham, or prawns and salad for unusual savoury sandwiches.
The flour is dumped into the milk mixture all in one go, and it needs to be stirred in thoroughly, as shown below. Choux pastry goes wrong if the next step is not properly followed. When I make choux pastry, I actually set the timer for 1 minute. Without the timer, there is a tendency to pull it off the heat before it's properly dried out.
If the pastry is not properly dried out at this stage, then the choux will not rise. It is steam that causes the pastry to rise, and if the pastry is too wet, this simply can't happen. You end up with solid uncooked sausages of dough! And there's no fix to this...
One minute has always sufficed for me - so you don't need to keep cooking for longer, otherwise, you end up with the opposite problem where the pastry is too dry.
I have also read that the quantity of eggs is flexible in choux pastry. Some people say that the quantity of eggs may need to be adjusted depending on the size of the eggs and the type of flour used. This is not something that I have ever needed to worry about - my choux pastry has worked perfectly every time using the method below. But it's something to bear in mind. Here's a link to the page where I found this discussion.
Get the ingredients measured first. Everything happens quite quickly and you really need to be ready.
Put the milk, water, butter, salt and sugar into a reasonably heavy pan and put on a low heat. If you are using any flavourings, such as a pinch of paprika, add them now.
Heat slowly to melt the butter. Once the butter is melted, bring the milk to the boil.Once it has come to the boil, remove the pan from the heat and add the flour - quickly and all in one go. Mix thoroughly with a wooden spoon until completely smooth.
Return the pan to a medium heat and stir continously for about 1 minute to slightly dry out the paste. Remove from the heat.
Add the eggs, one by one, beating with a wooden spoon all the time until the pastry is smooth and silky.