Mix the egg whites into a solid mass. Separately beat egg yolks with sugar and added one after another, ground walnuts, chocolate powder, cocoa, cinnamon, vanilla flavor and finally melted chocolate and butter (melt over the hot water). Finally, add the egg whites.
Divide the mass in a half.
In the first half add the baking powder and bake in a preheated oven for 45 minutes at 150 ° C. /302°F
In the second half, add crumbled biscuits and let cool to room temperature (not in the refrigerator because it will be over-tighten and will not be easily cover off the cake).
Baked and cooled sponge cake cover with other part of the mixture in which you put biscuits and decorate as desired. Proposal decoration: Melt sugar, pull out a few threads of this caramel and cover the cake. Quickly and effectively, try you will see.