Place the condensed milk and bananas in a mid-sized microwave-safe bowl.
Place the bowl in the microwave on high for 45 seconds.
Mash the warm bananas well into the condensed milk. Add the vanilla bean. Mix to combine and set aside.
In a separate large bowl, beat the butter and sugar until the mixture is light and fluffy.
Beat in the banana mixture until combined.
Beat in both eggs adding them one at a time until combined.
Mix in the salt and baking powder until combined
Mix in the flour until combined
Add the batter to the cake pan.
bake for 30-45 minutes or until a cake tester comes out clean. Leave to cool 10 minutes before turning out onto wire rack to cool completely.
For the Icing:
Make sure cream cheese and butter are at room temperature or the icing will be lumpy. Blend the cream cheese and butter in a medium mixing bowl until smooth.
Add the powdered sugar 1⁄2 cup at a time, blending after each addition.
Add the vanilla and hot water 1 tablespoon at a time until the icing is the desired consistency and can be poured (I like mine quite thick).
Pour the icing over the cooled cake and decorate with sprinkles.