Preheat oven to 170 degrees celsius (fan-forced).
Grease and line the base and sides of a 20cm cake tin with baking paper and set aside.
Place the softened butter and caster sugar into the TM bowl and mix on Speed 3 for 30 seconds. Scraped down the sides of the bowl and mix for a further 15 seconds, speed 4.
Add the eggs, banana, vanilla extract and milk and mix for 10 seconds, speed 5.
Add the self-raising flour and bi-carb soda and mix for 10 seconds, speed 4.
Scrape down the sides of the bowl and repeat for a further 5-10 seconds or until completely combined.
Pour the mixture into the prepared tin and bake in the oven for 45 - 50 minutes or until golden on top and a skewer inserted into the middle comes out clean.
If the cake is over-browning, place foil over the top and continue to cook.
Leave in the tin for 15 minutes before turning out onto a wire rack to cool completely.
When the cake has cooled completely, place the cream cheese, softened butter, pure icing sugar and vanilla extract into the TM bowl and mix on Speed 5 for 15 seconds.
Scrape down the sides of the bowl and mix on Speed 5 for a further 5-10 seconds.
Spread the frosting over the top of the cake (or cut the cake in half and use half of the frosting for the middle and half for the top.