Piping bag fitted with 6B star nozzle
Preheat the oven to 180°C conventional oven (356° Fahrenheit/Gas 4). Adjust metal racks to the middle groove of the oven. Prepare a silicone baking mat on a shallow baking tray. Alternatively, line a shallow baking tray with non-stick baking
Using an electric mixer, beat the butter and icing sugar (confectioners’ sugar) until light and fluffy. Sift the corn flour and flour and beat into the butter mixture until just combined. Use your hands to mix in the lemon/orange zest and vanilla bean (or vanilla bean paste).
Note: 00 is a powder-fine Italian type of flour. It is made from soft wheat varieties, and is frequently used in Italian desserts and pastas. 00 flour is available in most supermarkets, Italian food stores and gourmet delicatessens.
Spoon the biscotti mixture into a disposable piping bag fitted with a 6B star nozzle. If you have lined the baking tray with baking paper, pipe 4 dots of dough under each corner of the paper to hold it in place for piping. Pipe fingers, about 7.5cm long and spaced evenly apart on the silicone baking mats (or non-stick baking paper). Refrigerate the biscotti for 30 minutes.
Remove biscotti from the fridge and bake for 12-15 minutes. Transfer to a wire rack to cool completely.
Place the chocolate into a small heatproof bowl (or small saucepan) over a saucepan containing hot water. Stir the chocolate using a metal spoon until melted.
Dip one end of the Biscotti viennesi into the melted chocolate, then place onto baking paper to set – buon appetito.
Tip – after dipping in chocolate, you could also dip the ends in finely chopped pistachios.