For Choux.

On a pan over medium heat, boil milk, water, butter, sugar, salt.

Once boiled, add flour and stir. Cook for about 2-3mins until film form to the bottom of the pan. Then, transfer to a bowl and cool.

Once cooled, add eggs one at a time to have each egg fully incorporated.

Transfer the choux to a piping bag with 5/8in tip.

Pipe on the baking pan with parchment paper. Press down until size is achieved, then swirl to avoid tip. Then brush some egg wash.

Bake for 30 mins in 190 celcius

For Custard filling.

Warm milk and vanilla on a pan.

On a bowl, add the egg yolks and the sugar. Whisk until color is light. Then, add cornstarch.

Once milk is warmed, temper the egg mixture. To temper, add a small amount at a time of the milk to the egg while continuously whisking. (To avoid scrambled eggs)

Once all are combined, transfer back the mixture to the pan under low heat continuously whisking until the mixture is thickened.

Transfer to a bowl and let cool. Cover with cling wrap which touches the mixture to avoid forming skin. Then refrigerate.