Melt 150g of the chocolate. Brush the inside of the cones with melted chocolate, place on a tray and allow to set for 10 minutes, if it™s a hot day refrigerate for 10 minutes.
Meanwhile, whip the cream and icing sugar to soft peaks. Fold in the mascarpone. Combine the espresso and Kahlua in a shallow dish. Dip one biscuit into the coffee mixture, place on a board and cut crossways into 2cm pieces. Transfer to a bowl. Repeat with remaining biscuits and coffee mixture. Fold the biscuits, blueberries and blackberries into the cream mixture.
Spoon the berrymisu mixture into the waffle cones and stand upright in tall glasses. Refrigerate for 2-3 hours until set. Grate the remaining chocolate and sprinkle over the cones. Serve with extra berries if desired.