Preheat your oven to 375˚F.
Line a baking sheet with parchment paper. Draw 12 circles on the parchment paper about 3-4 cm in diameter. Flip the parchment over so the ink is facing down. Set aside.
In a medium size saucepan, over medium-high heat, add water, butter, sugar and salt. Bring to a boil. The butter should be completely melted, and sugar and salt dissolved.
Remove the pan from the heat and dump in all the flour at once. Stir until the mixture forms a paste.
Return the pan to the element, reduce heat to medium, and continuously mix for another 2-3 minutes. The dough will form a ball, and a film will develop on the bottom of the pan. Keep mixing, pushing the dough around the pan, spreading it out and mixing it back into a ball. You want the dough to dry out slightly and become shiny.
Transfer the dough to the bowl of a stand mixer fitted with the paddle attachment. You can also use a handheld beater. Turn the mixture onto low speed to allow the dough to cool off and release steam.
Once cooled slightly, begin adding the eggs. You only want to add one egg at a time and allow the egg to become completely combined before adding another. The dough should be glossy and pipeable so that it holds the mounds you form them into.
Transfer the dough to a piping bag (a Ziplock bag works, too). Pipe the dough into the prepared circles. If there are any pointy tops, or uneven edges, simply dip your finger into water, and dab the tops and edges until smooth.
Bake for 30 minutes. Do not open the oven during this baking process.
After 30 minutes, turn the oven heat off, open the oven door to allow the steam to escape, and close it again, leaving the choux buns in the oven. Let the choux buns sit in the oven with the heat off for another 15 minutes. This will help the shell harden and prevent it from being too soft.
Remove from the oven and transfer to a cooling rack to cool completely.