Beat the egg yolks with the sugar into a light and fluffy cream. Separately, beat the egg whites into snow with a pinch of sugar and gently mix them with the yolks.
Stir the mixture with the sieved together flour and cocoa. Pour the mixture into a form, covered with paper baking and lightly greased, and put it in a well heated oven.
Leave the cake layer to cool and cut it into 2-3 separate layers. Whip the cream to powdery snow.
Start adding it to the liquid chocolate, spoon by spoon, and combine into a single cream. Stick the layers together with this cream and cover the cake with it on top.