Preheat oven to 400ºF.
In a medium saucepot over medium-high heat, combine water, butter and salt. Heat until butter has melted and water is boiling.
Add flour and cook, stirring constantly with a wooden spoon. Stir until mixture begins to create a dough ball in the center of the pot and the dough is completely pulling away from the sides of the pan, about 2 minutes.
Transfer mixture to a mixing bowl or the bowl of a stand mixer fitted with a paddle attachment. On low speed, add the eggs to the mixture one at a time, scraping the sides of the bowl well after each addition and beating until the bowl feels cool (the mixture should be very smooth and silky). Add in the cheese after the last addition of the eggs.