Strain the cherries, collecting the juice. Bring the cherry juice to the boil with the cake glaze, add the cherries again and let the compote cool in a tall glass bowl.
Beat the cold whipped cream with the cream stiffener until stiff. Mix the quark with sour cream and vanilla sugar until smooth and fold in the whipped cream.
Pour the quark cream onto the cooled cherry mixture and decorate the dessert with a little eggnog and the chocolate shavings.