How to cook
Begin to whip the egg yolks with the sugar until they turn to a fluffy cream. Slowly add the sifted flour and lemon rind. If desired, add a little cognac to the mixture.
Beat the egg whites into snow and combine the mixtures. Pour it into a not-too-large form, covered with baking paper and buttered. Put it to bake until ready on a low oven.
Let the ready layer cool a bit, but it needs to be slightly warm when cutting it into 3-4 separate layers.
Prepare the cream according to the instructions on the starch packets; optionally, you can use a different cream for the cake.