To measure the milk, I use the empty condensed milk can. First separate the eggs. Then put the egg yolks in a saucepan with the condensed milk and normal milk. Heat slowly and carefully while stirring until the liquid has thickened (this can take a few minutes. Please stir well so that the mixture does not hit!).
Remove from the hotplate and let cool down. Beat the egg whites with the vanilla sugar and a pinch of salt until stiff. Whip the cream until stiff and fold in the finished egg whites. Crumble the biscuits into small pieces.
First layer a layer of biscuits, then a layer of milk mass and then the cream protein mass in a mold, then start again with the biscuit, etc. I always put a leftover biscuit crumb on the top layer of the cream protein mass, it looks better than without it. Then chill for at least 2 hours (it tastes best pulled through).