1.Preheat oven to 180°C (160°C fan-forced). Grease oven tray and line with baking paper. Mark a 10cm circle on paper.
2.In a small bowl, beat egg whites with an electric mixer until soft peaks form. Gradually beat in sugar, beating until dissolved between additions. Stir in sifted flour, butter and extract.
3.Place ¼ cup of the mixture in small bowl, stir in sifted cocoa; spoon into a piping bag fitted with a small plain tube.
4.Place a level tablespoon of remaining mixture in centre of each circle on tray, spread evenly to fill circles. Pipe chocolate stripes across circles.
5.Bake about 5 minutes. Working quickly, lift cookies from tray, shape into cones. Cool on wire racks. Repeat with remaining cookie mixture.
6.Just before serving, fill cookie cones with ice-cream.