Preheat oven to 180 degrees C. Grease and base-line 3 X 15 cm or 2 X 20 cm round cake tins.
Sift the flour, cinnamon, and baking powder into a bowl. Chop 75 g pecans and add to the bowl, along with the desiccated coconut.
In the bowl of a stand mixer fitted with the paddle attachment, or with an electric hand-whisk, beat the eggs and both sugars on high for about a minute.
With a sharp knife, cut the top and bottom off the pineapple, and slice off the skin, including the ‘eyes’ then cut into slices, about 1 cm thick. Remove the cores with a knife or with an apple corer, and slice off any bits of the ‘eyes’ that you have missed. Then cut into little chunks, about 1cm in size and blot them lightly with a piece of kitchen roll to remove any excess juice. If you want to, cut a few larger chunks for the top of the cake. Weigh 140 g little chunks for the cake mixture. Keep the rest for decorating the cake. Mash the bananas with a fork. Add the fruit to the mixing bowl, followed by the vegetable oil, and vanilla extract and beat again.
Add half the dry ingredients, beat, then add the other half and beat again.
Pour into the prepared tins. Bake for about 30 minutes, until a skewer comes out clean. Remove from the oven and leave to cool in the tins on a wire rack for about 15 minutes before turning the cakes out onto the rack and leaving to cool completely. You can decorate straight away, or wrap in foil and place in a tin overnight and decorate the next day.
When you take the cakes out, leave the oven on, scatter the remaining pecans on an unlined, ungreased baking tray and toast for 5-10 minutes. Leave to cool then roughly chop (reserving a few whole ones for the top, if desired).
For the icing, beat the butter (if using)* until creamy, then beat in the orange zest and cream cheese and gradually sift in the icing sugar, beating well after each addition. Beat until fluffy, adding a little more butter / cream cheese / icing sugar as needed to get your preferred consistency. Use to ice the cakes together and on top. In between each layer of the cake, scatter a layer of chopped and toasted pecans and fresh pineapple chunks, and decorate the top with the rest.