In a medium saucepan, combine water and butter. Heat over medium until the butter melts and the mixture comes to a rolling boil.

Remove from heat and quickly whisk in the flour and salt until a smooth dough forms.

Allow the dough to cool slightly, then add eggs one at a time, mixing well after each addition until the dough is shiny and smooth.

Preheat your oven to 425°F (220°C).

Pipe the dough into round mounds on a baking sheet lined with parchment paper.

Bake for 20-25 minutes or until golden brown and puffed. Let cool completely before filling.

In a bowl, whip heavy cream until soft peaks form.

Gradually add powdered sugar and vanilla, continuing to whip until stiff peaks form.

Using a piping bag or a small spoon, fill each cooled puff with the whipped cream mixture.

Dust with powdered sugar if desired, and serve immediately.