Make the icing first:
Lightly grate rinds from oranges and lemons into a bowl. Be very careful not to grate too deep into the white part of the rind, as this can turn your icing a bit bitter.
Squeeze the juice from the lemons and oranges and mix with grated zest
Whisk in confectioners sugar until smooth
To make the cakes:
Preheat oven to 350 F
Make cake batter according to box instructions
Spray miniature muffin tins with non-stick cooking spray
Fill tins HALF way full with batter - not all the way to the top
Bake for 12 minutes or until done
While the cakes are still hot, dunk each cake into the icing completely and set on wire rack to drain off excess juice
Once glaze cools and hardens, they're ready to eat!