Preheat oven to 400°F (200°C) and line a baking sheet with parchment paper.

In a medium saucepan, combine water, butter, and salt; bring to a rolling boil over medium-high heat.

Add the flour all at once and stir vigorously with a wooden spoon until the mixture forms a ball and pulls away from the sides of the pan.

Remove the pan from heat and allow the dough to cool for 5 minutes.

Add eggs one at a time, beating thoroughly after each addition until the dough is smooth and glossy.

Drop rounded tablespoons of dough 2 inches apart onto the prepared baking sheet.

Bake for 25 to 30 minutes until the shells are golden brown and firm to the touch.

Transfer shells to a wire rack and poke a small hole in the side of each shell to allow steam to escape; cool completely.

In a chilled bowl, whip the heavy cream, 3 tablespoons powdered sugar, and vanilla extract until stiff peaks form.

Cut the tops off the cooled shells or use a piping bag to fill the centers with the whipped cream, then dust with the remaining powdered sugar before serving.