For the tropical syrup:
Squeeze the juice from the oranges into a pan and add a spoonful of sugar.
Bring to a simmer, stirring to dissolve the sugar, then add the peel and take the pan off the heat, allowing to cool.
Just before you use the syrup, remove the peel.
Once the cakes are ready, remove them from the oven and set them aside to cool, poking a few holes in the top with your skewer.
Pour over a couple of tablespoons of syrup on each cake, a little at a time and allow to sink in.
Leave in the tin for a further 5 minutes to settle, then remove and allow to cool completely on racks.
While the cakes cool, you can make the cream cheese icing.