Drain the peaches, catching the liquid. Save one peach half for garnish and cut into 8 strips, puree the remaining peaches with the mixer.
Mix the quark, yoghurt and sugar and add the 4 tablespoons of peach juice. Stir in the peach puree. Whip the cream, vanilla sugar and cream stiffener until stiff, then fold into the quark-yoghurt-peach mixture.
Put the chocolate cookies in a freezer bag, seal the bag and crush the cookies with a rolling pin until they turn into crumbs.
Divide the cream and biscuits into 3 servings. Alternating starting with the cream and ending with the biscuits, distribute the two masses either in a large bowl or in 8 dessert bowls. Decorate with peach wedges and mint leaves.