Bring water and butter to a boil and add flour at once.
Remove from heat and stir vigorously until a doughy, lump-free mixture forms.
Pour mixture into the planetary machine and let it run for a few minutes with the leaf hook to cool.
Then add the eggs a little at a time, increasing the speed to blend them better.
Once the mixture is complete, which should be creamy but not liquid, begin to shape to the desired size using a sac-a-poche with a smooth nozzle.
Bake at 180° for about 15/20 minutes with the valve open.