Cut oranges in half. Using a grapefruit knife, remove pulp from each half. Juice the pulp & reserve 1 cup for the cake mix.
Preheat oven to 350 F. In a medium bowl, combine cake mix, eggs, oil & 1 cup freshly squeezed orange juice. Mix until batter has no lumps.
Place the orange cups into a muffin tin & fill with about 1/4 cup each of the chocolate batter. Bake 25 minutes. Remove from oven & allow to cool.
In a bowl, blend cream cheese, vanilla & orange zest with a hand mixer until smooth. Add butter & mix on medium-high for a couple of minutes. Add powdered sugar & blend until topping is uniformly smooth. Place a dollop of topping on each dessert.
If you wish to bake these desserts over a campfire:
Wrap each orange loosely in aluminium foil, taking care to keep the oranges upright.
Place the wrapped oranges on the edge of the camp-fire, out of the direct flame but close enough to the embers so the cakes will bake.
After 25 – 30 minutes remove the cakes from the heat and carefully unwrap. You should see cooked cake peeking out of the orange cup. Leave to cool for 15 minutes before adding a dollop of topping or just eat as is.