Separate the eggs. Beat the egg whites with a pinch of salt until stiff. Slowly add the sugar and continue beating until the egg whites are stiff and glossy.
Add the egg yolks one at a time, incorporating each yolk carefully and slowly. Next, add the corn starch, vanilla extract, and finely grated lemon zest and combine. Heat the milk well
Mix: Very slowly pour the milk over the egg mixture. Keep the jug in the left hand if you are right-handed and the electric mixer in the right hand. Pour in a thin stream while mixing.
Cook: Bring to a simmer while whisking. You have to reach the consistency of a pudding. Keep whisking; it will not take long, depending on the size of the pot.
Preheat the ovenPastry: It is preferable to cut one of the pastry sheets into squares before baking, it will be much easier to cut the whole cake into pieces once it is baked.
Bake the puff pastry sheets one after another according to the packet's instructions or until golden brown. *Keep an eye on them and read the instructions. Leave to cool completely.
Fill: Place the uncut pastry sheet on a rectangular serving plate, press it gently if too puffed up. Spread the vanilla custard evenly on top. Place the pastry squares on top and press gently.
Serve: The cremsnit is best served on the day it is made, this way the pastry will still be crunchy. It is still delicious the next day, but the pastry will become rather soggy.
Serve: The cremsnit is best served on the day it is made, this way the pastry will still be crunchy. It is still delicious the next day, but the pastry will become rather soggy.