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

2 In a saucepan, bring the water and butter to a boil. Once the butter has melted, reduce the heat to low and add the flour. Stir vigorously until the mixture forms a ball and pulls away from the sides of the pan.

3 Remove the mixture from heat and let it cool for a minute.

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

5 Drop spoonfuls of the dough onto the prepared baking sheet, leaving enough space between them.

6 Bake in the preheated oven for 25-30 minutes or until the puffs are golden brown and puffed up.

7 Remove from the oven and let them cool completely on a wire rack.

8 In a saucepan, whisk together the milk, granulated sugar, cornstarch, and egg yolks. Cook over medium heat, stirring constantly, until the mixture thickens and comes to a boil.

9 Remove from heat and stir in the vanilla extract. Let the custard cool.

10 Cut the cream puffs in half horizontally and fill each puff generously with the cooled custard.

11 Dust the filled cream puffs with powdered sugar for a finishing touch.