Method

• 1.
  Whiz the pistachio kernels in a food processor until very finely ground – be careful not to overprocess or it will become a paste. Set aside.
• 2.
  In a clean bowl, whisk eggwhites and sugar to stiff peaks. Gently fold the ground pistachio into the eggwhite mixture, then add vanilla and stir until you have a soft, sticky batter.

• 3.
  Shape into 20 walnut-sized balls and divide between 2 baking paper-lined baking trays, spaced 3cm apart. Using your finger, make a shallow indent in the top of each one and place a whole pistachio in the indent. Chill in the fridge for 20 minutes to firm up.
• 4.
  Preheat oven to 170°C.
• 5.
  Bake amaretti for 25-30 minutes or until the bottom is set – they will feel quite soft, but will harden as they cool. Cool on the trays for 10 minutes, then transfer to a wire rack to cool completely.