Sprinkle the raspberries with approx. 1 tablespoon of sugar before defrosting, and add sugar if necessary. Drain on a sieve. Put the juice in a small saucepan and bring to the boil. Mix the cornstarch with water and thicken the raspberry juice. Add the remaining raspberries, stir briefly and allow to cool.
Mix the quark with sour cream, yoghurt and lemon juice, mix everything with the vanilla sauce powder until creamy, season with honey, sugar, salt and a little cinnamon. Fold in the whipped cream.
Layer the Qark mass, raspberries and crumbled speculoos in a form (or serving molds) and sprinkle the last layer of chocolate shavings. Chill for about 30 minutes.
Mixed forest fruits or sour cherries can also be used instead of raspberries.