Preheat oven 150C. Place the hazelnuts in an oven tray and dry-toast in the oven until golden, about 20 minutes. Cool. Then tip onto a tea towel and rub to remove the skins. Grind until fine in a food processor/ grinder.

Cream the soft butter and sugar in a food processor. Add the egg and vanilla and process again until smooth and creamy. [A tip from my Nana - always use room temperature eggs when baking or the mixture may split at this stage]. Add the ground hazelnuts, orange zest, salt, flours and baking powder and pulse until the mixture comes together, scraping down the sides and pulsing again. [If making gluten-free cookies - at this stage put the food processor bowl with the cookie dough into the fridge and chill for 20-30 minutes. I find the gluten-free flours need to settle a bit before rolling or the dough will be too soft.]

Preheat the oven 180C. Roll the dough into walnut-sized balls and arrange evenly spaced on a lined baking tray. Press with your fingers or a fork to shape into cookie rounds. Bake for 20 minutes until golden. Cool on a cake rack.