Slowly melt the chocolate in a little cream, add the gingerbread spice. Soak gelatin in water and melt in the microwave. Add to the chocolate melt. Whip the cream. Beat egg whites until stiff. When the chocolate melt has cooled to hand temperature, fold in the cream first, then egg white. Pour into a box cake tin, refrigerate for 2 hours. Put morello cherries in a saucepan with juice, bring to the boil and thicken with cornstarch. Turn the mousse out onto a plate, garnish with chocolate sprinkles and serve with cherries.