Soak gelatin. Beat the egg with lemon juice and vanilla sugar until frothy, mix the yogurt with the jam and add to the egg mixture. Squeeze out the soaked gelatine and dissolve in the 5 tablespoons of orange juice over a mild heat. Stir carefully into the yogurt mixture. Refrigerate.
As soon as the cream starts to gel, fold in the whipped cream. For 3-4 hours in the refrigerator and let set.
Squeeze the 2 oranges, stir in the teaspoon of Mondamin and heat.
Spread the sauce on the dessert plate and cut off the dumplings from the yoghurt cream. Garnish with lemon balm.