01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together gluten-free flour, cocoa powder, baking soda, sea salt, and instant espresso powder until thoroughly mixed.
03 - In a large bowl, beat softened butter, brown sugar, and granulated sugar until pale and fluffy, about 2 to 3 minutes using an electric mixer.
04 - Add eggs one at a time, mixing well after each addition, then blend in vanilla extract.
05 - Gradually add dry ingredients to the wet mixture, blending on low speed just until combined.
06 - Gently fold in dark chocolate chips and chopped pistachios using a rubber spatula.
07 - Scoop tablespoons of dough onto the prepared baking sheets, spacing about 2 inches apart.
08 - Bake for 10 to 12 minutes, or until edges are set while centers remain slightly soft.
09 - Let cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack until fully cooled.