Grind the pistachios, put the flour in a bowl and knead with all the ingredients to form a dough, shape it into a ball, flatten it a little and wrap it in cling film. Place in the refrigerator for at least 2 hours.
In the meantime, line a baking sheet with parchment paper.
Take the dough into walnut-sized balls and shape them into croissants. Place on the prepared baking sheet and cover with cling film and place in the refrigerator for another hour.
Preheat the oven to 180 degrees and then bake the croissants for 15-20 minutes. They should be light in color at the bottom, but still light at the top.
While it is still hot, roll it carefully in powdered sugar that has been placed on a plate.
Let the croissants cool completely on a wire rack.
Depending on the size, the dough makes 15-20 pieces.