Preheat oven to 350 degrees and line two baking sheets with parchment paper.
Grind 1/2 cup of pistachios in a small blender or food processor until fine pieces, saving the other 1/2 cup of pistachios for later.
In a medium bowl whisk together flour, baking powder, baking soda, and salt.
In a large bowl cream together butter, brown sugar, and maple syrup until a little bit fluffy.
Add in egg yolks, vanilla, and blended pistachio pieces. Blend for a couple minutes.
Add dry ingredients to wet ingredients and blend some more. Mix in chocolate chips and remaining 1/2 cup of pistachios chopped roughly.
Roll batter into about 1.5 tbs sized balls- about 8-10 to each sheet pan. Bake for roughly 11 minutes, until golden on the outside.
As soon as cookies come out, top with flakey sea salt.