My First French Cream Slice (Crème Slice) – Don’t Lose This Recipe!

Ingredients:
For the pastry:
2 sheets puff pastry

For the cream:
1 liter milk
200 g sugar
2 packets vanilla pudding powder (or 80 g cornstarch)
4 egg yolks
1 tsp vanilla extract
50 g butter

For topping:
powdered sugar