How to make
Beat the egg with the milk and granulated sugar in a pot on the stove and stir until slightly thickened. Add the starch, pre-diluted in a little water and stir the cream until thickened. Remove from the heat and add 1 lump of butter.
Leave to cool, and in the meantime, beat the cream with the powdered sugar and vanilla. Once the egg cream cools, mix it thoroughly with the cream mixture.
Begin to stack the cake, by putting a little cream on the bottom of the pan or form you are using. Arrange a layer of biscuits dipped in milk, a cream layer, then sprinkle with walnuts, biscuits again and so on until out of products. Top the cake with cream.
To decorate, crush some biscuits with 1 tablespoon of cocoa and sprinkle this over the cake.