Melt both chocolates in a double boiler. Beat the egg and yolk with the powdered sugar in a water bath to a cream. Add the chocolate and stir. Stir in the whiskey and orange peel, let the mixture cool down a little.
Whip the cream until stiff and carefully fold it into the cooled cream. Spread on glasses or bowls and refrigerate for about 3 hours. Serve garnished with chocolate chips.