Freeze 1 tbsp balls of pistachio cream for easy stuffing.
Brown the butter in a saucepan until amber with specks, then chill for 5 minutes.
Whisk in both sugars, then the egg and vanilla.
Fold in flour, baking powder, baking soda, and salt.
Stir in chocolate and crushed pistachios.
Scoop 3 tbsp dough balls, flatten, and stuff with a frozen pistachio cream ball. Seal completely.
Chill dough balls for 30 minutes. Preheat oven to 350°F / 175°C.
Optional: spoon extra pistachio cream on top of the dough balls.
Bake for 12–14 minutes, until edges are golden.
Use a circular tool to “scoot” cookies into round shapes.
Cool 5 minutes on tray, then transfer to a wire rack.