Using hand-held electric beaters or a stand mixer, beat together the melted butter and sugars in a bowl until well combined. Add the egg and vanilla extract and beat until glossy.
Sift the flours, bicarbonate of soda, baking powder and salt into another bowl and mix well. Add the dry ingredients to the wet ingredients and beat on a low speed until just combined. Add the chocolate and hazelnuts and stir until just combined.
Line two baking trays with baking paper. Using a large ice-cream scoop or spoon, measure out the dough into 10 balls, weighing approx. 120g each. Place on the baking trays, 5cm apart and put in the fridge for 20 minutes to firm up.
Meanwhile, preheat the oven to 180C/160C F/Gas 4. For perfect circle-shaped cookies, place each dough ball in a 10cm metal egg ring and press the dough right to the edge. Bake for 14 minutes or until the tops are golden. Remove from the oven and gently work any cookie that’s risen over the edge back into the ring, so it’s easy to remove once cooled.
Alternatively, bake as balls, spaced well apart on the trays for 14-16 minutes until golden and crisp around the edges.
Cool on the baking trays for 10 minutes, then transfer to a wire rack to cool completely. Remove the rings, if using, from the cookies and serve.
Recipes and photographs taken from Eat NYC by Yasmin Newman, photography by Alan Benson, (Smith Street Books, £35)
