Zest lemon and orange and juice both. Mix the juices with brown sugar. Preheat the grill. Roughly chop chocolate.
Grill bananas in their skin until they are black on the outside and soft on the inside. Make a lengthwise incision and fill with chocolate. Grill for another 5 min. Drizzle some of the sugar mixture on top and serve hot with a scoop of vanilla ice cream.