How to cook
Beat the eggs in a bowl, add the water, cognac, salt and vinegar.
Separately, sift the flour, then add the egg mixture and chopped into pieces margarine and knead a soft, nonstick dough. Add more flour if needed. Wrap the dough in plastic wrap and put it in the fridge for 2 hours.
In the meantime, make the cream. Set aside 1 1/5 cups (300 ml) of the cold milk, pour the rest into a pot. In another metal container, beat the egg yolks with the sugar, add the flour and while stirring nonstop, pour in the set aside cold milk in a thin trickle, until you get a smooth mixture.
Put the container on low heat and use a ladle to add in the hot milk while stirring nonstop until the cream thickens. Then remove from the heat. Add the vanillas and chopped butter and stir until the butter melts. Wrap the cream with plastic wrap and leave it to cool completely.
For the layers, divide the dough into 12 equal parts and shape balls. Roll out a ball into a very thin sheet on top of baking paper and cut out a circle using a plate. Bake it along with the cut out parts in a moderate oven. Repeat this process for all 12 balls.
Set aside the cut out parts and crumble them with a rolling pin onto a sheet of baking paper. You're going to need them to sprinkle over the cake.
Assemble the cake by alternating between cake layer and cream, finish off with cream. Smear the cake with cream on the sides. Sprinkle the crumbled parts generously over it on all sides.
Leave it in the fridge for at least 12 hours before serving.