In a food processor, pulse pistachios into small pieces (see photos). Do not process too much and end up with pistachio butter. Make sure to stop when the nuts end up in small pieces.
Then add the almond flour and powdered sugar to the food processor. This will help prevent the pistachios turn into butter. Continue pulsing until the whole mixture turns finer almost like coarse coffee grounds
In a small bowl, whisk the egg white until a little foamy. Add these into the processor and blitz until you can press the mixture together in your hands
Shape the mixture into a log and wrap in plastic. Chill for 1 hour
Preheat oven to 340℉
Remove the mixture from the fridge and shape into ¼ inch thick discs. Roll these into balls
Fill a bowl with some powdered sugar and coat each ball in the bowl. After each coating, place the cookie on a baking sheet lined with parchment paper.
Once all cookies have been coated and placed, use your finger to press a shallow pit in each cookie and place a single, whole pistachio
Bake the cookies for 12 to 15 minutes until the outside dries but the inside remains soft
Remove from the oven and let cool before serving
