Wash off 1 orange, dry with paper towels and rub the peel off. Thoroughly peel the remaining oranges. Cut the fillets out of the separating skins over a bowl, collecting the juice.
Put the yogurt, sugar, vanilla sugar, eggnog, the grated orange peel and 5 tablespoons of orange juice in a large bowl. Mix everything together until smooth.
Soak the gelatine in cold water for 5 minutes, squeeze it out and dissolve it in the warm cream.
Whip the cream until stiff and fold into the cream. Put both in dessert bowls and refrigerate for 1 hour.
Sprinkle with chocolate sprinkles and decorate with mint leaves.