Napoleonbakelse (Swedish Napoleon cake)

Instructions

1. Preheat the oven to 200 °C and cut the puff pastry into three equal rectangles.
2. Prick each sheet with a fork and bake for 12 to 15 minutes until golden brown, then let them cool.
3. Heat the milk with the split vanilla pod, then leave to infuse for 10 minutes.
4. Whisk the yolks with the sugar and cornflour, then pour the hot milk over them while stirring.
5. Return the mixture to the pan and cook over medium heat, stirring until it thickens, then remove from the heat, add the butter and vanilla and let it cool.
6. Stack the pastry layers with the custard between each one, then coat the top with an icing made from icing sugar and water. Let it set before cutting into squares.