Separate the egg yolks from the whites. Beat the egg yolks with half the sugar and while stirring continuously, put them to steam, stirring for 1-2 minutes. Be careful not to cook them.
Once slightly cooled, add the crushed chocolate, ground walnuts, flour and stir until uniform. Beat the egg whites into hard snow with the remaining sugar and stir them into the mixture with the egg yolks.
Bake 3 separate walnut cake layers, of the same size.