Cake 1 1/3 cup unsalted butter, softened1 1/3 cup brown sugar1 cup castor sugar2 tsp vanilla extract5 eggs1 cup sour cream or yogurt3 ripe bananas, mashed1 cup chopped white chocolate4 cups self-raising flour, siftedIcing1/2 cup unsalted butter, chopped, softened1 1/2 cups pure icing sugar2 cups cream cheese, chopped, softened3 tsp vanilla bean paste
DirectionsPreheat oven to 350˚F. Grease and line the base and sides of two 15cm round cake pans. Beat butter and sugars together in an electric mixer until thick and fluffy. Add the vanilla extract, then the eggs, one at a time, beating well after each addition. Beat in the sour cream and bananas, then fold through the white chocolate and flour. Divide between pans and bake for 1 hour 40 minutes until a skewer inserted in the centre comes out clean. Cool completely in the pans then invert and slice horizontally in half.
For the icing, place butter and icing sugar in an electric mixer and beat until pale. Add cream cheese and beat for 8 minutes until thick and fluffy. Place one cake layer on a cake stand and spread with 1/3 cup icing. Top with another cake and repeat with remaining two layers.
Finish with a layer of cake then take 3/4 cup of icing and using a palette knife, spread over the outside of the cake, carefully scraping along the edges to remove any crumbs. This is your crumb layer, which will ensure no crumbs ends up in your final layer of icing. Spread remaining icing over the cake. Chill for 30 minutes then serve.