In a large mixing bowl, combine the flour, baking powder, and salt.

In a saucepan, heat the water, milk, and butter until the butter is melted and the mixture is warm.

Pour the warm liquid into the dry ingredients and mix until well combined.

Add the eggs one at a time, mixing well after each addition until the dough is smooth and elastic.

Let the dough rest for 30 minutes in the refrigerator.

In a medium saucepan, heat 500ml milk over medium heat until it is warm but not boiling.

In a separate bowl, whisk together the sugar, flour, and eggs until smooth.

Gradually add the warm milk to the egg mixture, whisking continuously to avoid curdling.

Return the mixture to the saucepan and cook over medium heat, stirring constantly until the cream thickens to a custard-like consistency.

Remove from heat and stir in the butter until fully melted and smooth. If desired, add a few drops of vanilla flavor.

Allow the cream to cool to room temperature.

Preheat your oven to 180°C (350°F) and line a baking sheet with parchment paper.

Roll out the chilled dough on a lightly floured surface to about 1/4 inch thickness.

Cut the dough into desired shapes (e.g., circles or squares) and place them on the prepared baking sheet.

Bake for 15-20 minutes or until the pastries are golden brown and puffed up.

Remove from the oven and let cool completely.

Once the pastries are cooled, cut them in half or create a pocket if desired.

Spoon or pipe the cooled cream filling into the pastries.

Dust with icing sugar before serving for a touch of sweetness and decoration.