Pistachio biscotti

Preheat the oven to 170 ºC (340 ºF) and butter a large baking sheet or spray with nonstick spray. Lightly dust the baking sheet with flour, shaking off any excess. Cream the butter and sugar together until light and fluffy. Add the orange rind and vanilla essence and mix well. Add the eggs one at a time, beating well after each addition. Sift the flour, baking powder and salt together, and add to the mixture. Stir in the chopped chocolate and pistachio nuts. Chill the dough for 30 minutes or until no longer sticky. Turn the dough out on to a floured surface and divide in half. Shape each piece of dough into an oblong. Place the 2 pieces of dough on the baking sheets and bake for about 30 minutes or until the dough just begins to change colour. Allow to cool on a wire rack for about 5 minutes before transferring to a wooden board and cutting into diagonal slices. Return the slices to the baking sheet and bake for 7 minutes on each side. Cool the biscotti on a wire rack and store in an airtight container. Makes 7 dozen biscotti.