In a large saucepan, combine the water, butter, sugar and salt and bring to a boil.
Reduce the heat to moderate. Add the flour all at once and stir vigorously with a wooden spoon until a tight dough forms and pulls away from the side of the pan, 2 minutes.
Remove the pan from the heat.
Begin adding the eggs 1 at a time, stirring vigorously between additions until the eggs are completely incorporated and the pastry is smooth.
The dough should be glossy and very slowly, stretch and fall from the spoon in wide ribbons.
Cover the dough with plastic wrap and allow to chill in the fridge for 1 hour.
Preheat the oven to 425°/218°C and line a baking sheet with parchment paper.
Transfer the dough to a piping bag fitted with a 1/2-inch plain tip. Pipe 1 1/2-inch mounds onto the baking sheets, leaving 1 inch between them.
Put your puffs into the oven and turn the heat up to 450°/230°C and bake for 10 minutes.
Reduce heat to 350°F/176°C and finish baking for another 15 minutes, until golden brown.
Remove from oven and pierce a hole in the top or the side of each of the puffs with a toothpick. This allows the steam to escape and your puffs to hold their shape.