How to bake a chocolate cake in an orange

Tom Fassbender says: "The last time the family went on a camping trip, we made Breakfast in a Bag. We always like to have a cooking adventure when we camp, so this time we baked chocolate cake in oranges. The results were predictably delicious."

How to bake a chocolate cake in an orange (Via Boing Boing's G+ community, which is a terrific happy mutant hangout. Also, Cory posted the original recipe earlier.)