How to make
Beat the egg whites to snow with the sugar. To the yoghurt, add the flour with the baking powder, vanilla, the greater part of the walnuts and whites.
Divide the mixture into 3 equal parts, bake them 1 after the other in a tray, laid out with baking paper.
Beat the egg yolks with the powdered sugar until whitened. Add the cocoa and margarine and beat until you get a smooth cream.
Smear the cooled layers with the cream and sprinkle with the remaining ground walnuts.