Soak the gelatine. Bring milk and espresso powder to the boil, remove from the stove. Let it cool down a little. Squeeze the gelatine and dissolve in the milk. Separate the eggs. Whisk the egg yolks. Gradually stir lukewarm milk into the egg yolk.
Put the mass in a cold place. As soon as the mixture begins to set, beat the egg whites until stiff. Gradually add sugar. Fold the beaten egg whites into the mocha mixture. Whip the cream until stiff. Put 4 tablespoons of cream aside.
Fold the rest of the cream into the mocha cream and chill for at least 1 hour. Wash the orange hot. Peel in thin strips with a julienne knife. Pour the rest of the cream into a piping bag with a star-shaped spout.
Spray cream tuffs on the cream. Pour a little eggnog over it. Decorate the cream with orange peel and, if desired, with wafer rolls and a little espresso powder.