Preheat the oven to 200°C.
Place pastry on a non-stick baking sheet.
Whisk egg white and icing sugar together in a bowl.
Spread the sugar mixture over the pastry.
Bake the pastry for 15 minutes.
Cut the baked pastry into four squares.
Whisk egg yolks and caster sugar until pale and frothy.
Heat milk and the vanilla pod in a pan until boiling.
Discard the vanilla pod and whisk the hot milk into the egg mixture.
Stir the custard in a clean pan over low heat until thickened.
Layer pastry squares with custard and dust with icing sugar to serve.