1. Preheat oven to 190°C/375°F/Gas 5.
2. Grease and baseline with grease proof paper 2 x 8 / 20cm sandwich tins.
3. Beat butter and sugar together until smooth and creamy.
4. Add the eggs and vanilla extract and beat for 30 seconds.
5. Next mix in the banana and buttermilk. Finally, sieve in flour, bread soda and salt.
6. Gentle stir to combine. Divided mixture evenly between two prepared tins.
7. Bake in centre of the oven for 25 minutes, or until well risen and firm to the touch.
8. Remove from the oven, leave in tin for 10 minutes.
9. Turn into a wire tray to cool.

To Assemble Cake

1. Meanwhile make the icing by putting all Ingredients into a mixing bowl. Beat until smooth.
2. Spread two thirds of the icing on both halves of the cake.
3. Slice and arrange the bananas on one half of the cake and place the other half on top.
4. Spread remaining icing on top of the cake.