How to make
Separate the egg yolks and whites. Beat the soft butter with a mixer along with the sugar. Add flour, cocoa, egg yolks and rum. You will get a heavy dough. Add the beaten to stiff snow egg whites.
Gently stir and put it into a buttered baking dish. Place all the walnut halves next to each other. Bake in a moderate oven at 340°F (170 °C) for about 40-45 minutes.
Cut the cold cake into rectangular pieces.
