Roughly chop the chocolate and melt it in a bowl over a warm water bath. Take about 16 raspberries aside. Puree remaining raspberries and icing sugar and pass through a sieve.
Stir mascarpone and milk until smooth. Stir in sugar, quark and vanillin sugar and season to taste with some lemon juice. Add chocolate to the cream, stir in briefly and fill into glasses immediately. Decorate with raspberries and drizzle with the sauce.