Finely grind the biscuits in a food processor. Melt the butter in a saucepan and add the crumbs. Stir well, then pour the mixture into a greased springform pan lined with baking paper.
Spread the mixture evenly over the bottom of the pan and press down firmly with the rounded side of a spoon. Place the base in the refrigerator.
Soak the gelatin sheets in a bowl of cold water for at least 10 minutes. Put the quark in a bowl. In a separate bowl, whip the cream with the vanilla paste and sugar until stiff.
Heat the milk over low heat. Squeeze the gelatin sheets and dissolve them in the milk, stirring constantly. Remove from heat. Allow the mixture to cool slightly. Add it to the quark, stirring constantly.
Fold the whipped cream into the quark mixture. Roughly mash the raspberries and add them to you quark as well. Fold them through.
Pour the quark mixture over the base, then stick a few extra raspberries into the top, leaving them partially exposed.