Preheat your oven to 375°F and line a baking sheet with parchment paper or silicone mat.

In a large saucepan, add the water, unsalted butter, salt, and sugar. Bring this mixture to a boil over medium-high heat and then remove from the heat.

Quickly stir in the flour using a wooden spoon until well combined—this should take about a minute.

Place the pan back on the stove and cook the mixture, stirring continuously until you see a film start to form on the bottom of the pan.

Transfer the dough to a large bowl and let it cool slightly.

Add four eggs one at a time, making sure to incorporate each egg completely before introducing the next.

For the egg wash, whisk together the remaining egg with 1 tablespoon of water and set aside.

Using a large disposable pastry bag fitted with a round tip, pipe 2-inch circles onto the prepared baking sheet.

Moisten your finger with water and gently smooth out any pointed peaks on the pastry.

Brush the tops with the egg wash, and bake for 25-30 minutes, or until golden brown.

Remove from the oven and allow to cool completely on wire racks.

In a mixing bowl, combine the very cold heavy cream, powdered sugar, and vanilla extract. Whip until soft peaks form.