How to cook
In a pot, boil the milk with the sugar. Gradually, add the mixture of pre-beaten egg yolks, the flour and cocoa dissolved in the water, while stirring nonstop. Keep it on the stove for 3-4 min. and remove. Let it cool slightly.
Set aside some of the resulting cream for smoothing out the cake, pour the rest of it onto the cake layer and let it cool and harden in the fridge.
Take the cake out of the form, and smear it with the remaining cream all over, sprinkle it with white chocolate or other flakes.