Cream butter and sugar. Beat in eggs. Combine flour, baking powder, bicarb soda, salt and vanilla sugar then mix into the butter sugar mixture. Stir in the banana until it's well combined then fold in chocolate and nuts.
Pour into a greased cake tin then bake in preheated oven until a knife inserted into the centre comes out clean, about 1 hour. Allow to cool before icing with your favourite icing.
Excellent cake. The chocolate and nuts raise it above a normal banana cake. I used brazil nuts which worked very well. I didn't have vanilla sugar so added a teaspoon of vanilla essence instead. I probably used too larger cake tin, a 20 - 23cm round would have given better depth to the cake. - 01 Mar 2013