Walnut Cake Recipe

1. Heat the oven to 180°C or 360°F.
2. Beat 6 egg whites with half the sugar and set aside.
3. Beat 6 egg yolks with the butter and remaining sugar.
4. Add the beaten egg whites,  the walnuts and the biscuits to the yolks and mix gently. 
5. Pour into a greased and floured form.
6. Bake for about 30 minutes, let it cool and cut in half so you have two layers.

Filling:

1. Heat the condensed milk, the cocoa powder and the the one egg yolk left and cook until it thickens, without stopping to stir.
2. Spread this filling over one layer of the cake, add the second cake layer on top and use the remaining cream on top.