1. Preheat your oven to 150C.

2. Toast the hazelnuts for 25-30 minutes until golden and fragrant. Place the toasted hazelnuts in a tea towel and rub the skins off as best as you can. Roughly chop. Set aside. Leave the oven on at 150C.

3. In a medium sized bowl, whisk together the flour, cocoa powder, bi-carb soda and salt.  

In a small food processor combine half the dry ingredients and all of the chocolate. Process until the chocolate is very finely chopped and looks like almond meal. Mix this with the remaining dry ingredients and set aside.

4. In another medium sized bowl, use a wooden spoon to beat the butter and sugar together for about 2 minutes. Add in the eggs and switch to a whisk and whisk until fully incorporated. Add in the vanilla and orange zest and stir to combine.

5. Switch back to your wooden spoon and add the dry ingredients to the butter mixture. Stir in the hazelnuts.

6. Set up a flat sheet tray with a sheet of baking paper. 

7.Tip the dough onto the tray and shape it into a loaf shape in the center of the tray approximately 32cm long and 14cm wide. Chill the dough in the fridge for 15 minutes.

8. Bake at 150C for 40-45 minutes until the dough springs back to the touch. Remove from the oven allowing the dough to fully cool. Leave the oven on.

9. Use a serrated knife to cut biscotti into 1.5cm thick slices and lay those on 2 sheet trays so they lay flat. 

10. Bake at 150C for 20 minutes until crisp. Allow to cool.

11. Store in an airtight container and they will be good for about a week.