Place biscuits in food processor and pulse until crumbs. Place chocolate in heat-proof bowl over a saucepan of water making sure the water doesn’t touch the bowl. Heat water to melt the chocolate. Add quark, coconut and rum into crumbed biscuits and process until combined. Add melted chocolate and continue processing until combined. Refrigerate for 1 hour then roll into balls and roll in coconut. Refrigerate until needed.