Preheat the oven to 160°C fan assisted. Place thirty large cupcake cases into muffin tins.
Sieve together the flour, sugar, bicarbonate of soda, salt and cinnamon (dry ingredients).
Whisk together the oil, eggs, pineapple, vanilla extract and bananas. Stir in the chopped walnuts. (wet ingredients).
Add the dry to the wet ingredients, folding in carefully until completely combined. Using an ice cream scoop divide the mixture between the cupcake cases.
Bake in the preheated oven for twenty minutes until a skewer inserted into the centre of a cake comes out clean. Cool on a wire rack
To make the topping beat together the cream cheese, softened unsalted butter and the vanilla extract. Gradually beat in the icing sugar to form a stiff but spreadable topping.