For the blueberry tartlets, whip the whipped cream, mix well the QimiQ Vanilla with the sour cream, buttermilk and sugar. Fold in approx. 300 ml whipped cream. Pour the remaining whipped cream into a piping bag and chill.
Fill the mug with some cream, spread cocoa cake pieces on top and pour some cream on top. Press some blueberries into the cream.
Soak the gelatine in cold water and dissolve it in some warm blueberry juice. Puree about 300 g blueberries with blueberry juice, stir in gelatine and spread over the cream.
Refrigerate for a few hours, preferably overnight. Decorate with remaining blueberries, whipped cream and white chocolate decor pieces.