01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - Whisk together gluten-free flour, baking soda, and salt in a medium bowl. Set aside.
03 - Beat softened butter, granulated sugar, and brown sugar until light and fluffy, approximately 2 minutes.
04 - Mix in egg and vanilla extract until fully incorporated.
05 - Gradually add dry ingredients to wet mixture, mixing until just combined.
06 - Gently fold chopped pistachios and white chocolate chips using a spatula.
07 - Drop tablespoon-sized dough portions onto prepared baking sheets, spacing 2 inches apart.
08 - Bake 10 to 12 minutes until edges are lightly golden and centers appear set.
09 - Allow cookies to rest on baking sheet for 5 minutes, then transfer to wire rack to cool.