Mix the flour, castor sugar, salt, baking powder and chopped nuts together.
Mix the eggs, vanilla extract and zest together.
Mix both mixtures together to form a dough. Do not over mix.
Roll and shape.
Place on a buttered tin and bake at 1800C for 15 minutes.
Let it cool. Cut the biscotti with a serrated knife in 1cm thick slices. Place on a lined tray and bake at 1400C for another 25 – 30 minutes or until dry.