How to make
Melt the butter in a microwave oven. Beat the sugar and melted butter with a mixer until whitened.
Add the eggs 1 by 1, while beating with the mixer until the cream becomes fluffy.
Sift the flour, baking powder and cocoa and pour them gradually into the mixture. Finally, add the chopped walnuts and beat everything until homogeneous. Pour it into a greased and floured oven dish.
In another bowl, whip the egg with the powdered sugar and cottage cheese until homogeneous. Pour it into a pastry bag and spray it out in a spiral on top of the brown mixture in the oven dish.
Bake the cake at a moderate temperature for about 45 min. Check to see if it's ready with a toothpick.