Preheat oven to 400 degrees F.
In a medium saucepan, heat water, butter, sugar and salt. Bring to a boil.
Remove the pan from the heat and add the flour. Stir until the mixture is a paste.
Return the pan to the heat and continuously stir the mixture until it's slightly shiny, about 2 minutes. You also want to make sure a thin film forms on the bottom of the pan.
Transfer the paste to the bowl of a stand mixer fitted with the paddle attachment.
Beat on low until the choux has slightly cooled, about 1-2 minutes.
Add one egg at a time, beating until it has fully combined before adding the next. Beat the batter until it's smooth and light. Transfer the dough to a piping bag fitted with a round or star tip. Or you can scoop dough by the tablespoon.
Line a cookie sheet with parchment.
Pipe the dough into 1+1/2 to 2 inch mounds. Leave about 2 inches between each mound.
Lightly dab the tops of each mound with a wet fingertip to slightly smooth the surface.
Bake for 15 minutes at 400 degrees F.
Reduce the heat to 350 degrees F, and continue to bake for another 15 minutes, until the mounds are golden brown, light and airy.
Immediately after removing from the oven, cut a small 'x' in the side of each puff, to allow the steam to escape.
Cool completely on a cooling rack.