Viennese finger biscuits

1) Preheat the oven to 180°C/350°F/Gas Mark 4.
2) Cream the butter and icing sugar until light and fluffy.
3) Sift in the flour and cornflour and beat well.
4) Line two baking trays with grease-proof paper.
5) Put the mixture in a piping bag and pipe fingers, about 7cm long, evenly spaced on the paper.
6) Bake for 15 mins.
7) Allow the biscuits to cool on the baking tray.
8) Melt the chocolate in a small bowl over a pan of hot water.
9) Dip the ends of the fingers in the chocolate and place on grease-proof paper to set.