01 -
Pulse half of the pistachios (1/3 cup) in a food processor until finely ground and set aside. Pulse the remaining pistachios a few times for a coarse chop and set aside separately.
02 -
Melt the butter until just liquid and allow it to cool to room temperature.
03 -
In a small bowl, combine the all-purpose flour, baking soda, and kosher salt. Set aside.
04 -
Whisk together the melted butter, light brown sugar, and granulated sugar until smooth. Add the whole egg, egg yolk, and vanilla extract, stirring until fully incorporated. Fold in the finely ground pistachio crumbs.
05 -
Add the dry ingredients into the wet mixture and stir until just combined. Gently fold in most of the coarsely chopped pistachios and the chopped chocolate, reserving some for garnish.
06 -
Cover the dough and refrigerate for at least 30 minutes, up to 2 days. For extended storage, freeze the dough.
07 -
Preheat the oven to 350°F. Line a baking sheet with parchment paper or a silicone mat. Portion the dough into 18 balls, approximately 2 ounces each, spacing them 2 inches apart. Bake for 10 to 14 minutes until the tops are set.
08 -
Upon removal from the oven, press remaining pistachios and chocolate pieces into each cookie and sprinkle lightly with flake salt. Allow cookies to rest on the baking sheet for 10 to 15 minutes before transferring to a wire rack to cool completely.