Mix yogurt, sugar, vanilla sugar and lemon to a creamy mixture. Whip the cream until stiff and fold into the yoghurt mixture. Spread the yoghurt mixture on small preserving jars or dessert bowls and chill.
Thaw the frozen strawberry and mango mixture (or other fruit). Puree the fruits finely and chill.
Wash and prepare raspberries and blueberries. Just before serving, distribute the puree on the yoghurt jars, sprinkle with white chocolate shavings and garnish with the fresh berries.