For the cookies:

1. 1. Bake the hazelnuts at 180ºC (350ºF) for 15 minutes. Using a kitchen towel, rub off the skins. Set aside 50 g of hazelnuts and grind the rest into a coarse flour. Roughly chop the reserved hazelnuts into irregular pieces.
   2. In a large bowl, combine the hazelnut flour, powdered sugar, salt, and cocoa powder. Mix well and add the aquafaba, stirring until all ingredients come together into a sticky cookie dough.
   3. Divide the dough into 9 equal portions. Roll each portion between your palms to form balls, then gently press each one onto the chopped hazelnuts so they are coated on both sides.
   4. Preheat the oven to 175 °C (345 °F). Place the cookies on a baking tray lined with parchment paper. Bake for about 15 minutes, until lightly golden on top. Remove from the oven and allow the cookies to cool before transferring them to a plate (otherwise, they may fall apart).