01 - Preheat oven to 350°F. Line two baking sheets with parchment paper and set aside.
02 - In a medium mixing bowl, whisk together gluten-free flour blend, baking powder, baking soda, and fine sea salt.
03 - In a large bowl, beat softened unsalted butter, granulated sugar, and light brown sugar with an electric mixer until light and fluffy, approximately 2 minutes.
04 - Add egg, pure vanilla extract, lemon zest, and fresh lemon juice to the creamed mixture. Mix until thoroughly combined.
05 - Gradually add the dry ingredient mixture to the wet ingredients, mixing until just combined and no streaks of flour remain.
06 - Fold in coarsely chopped roasted unsalted cashews evenly throughout the dough.
07 - Scoop tablespoon-sized portions of dough and roll each into a ball. Coat each ball lightly in extra granulated sugar.
08 - Place dough balls 2 inches apart on prepared baking sheets. Gently flatten each with your fingertips or the bottom of a glass.
09 - Bake for 10 to 12 minutes, until edges are golden and centers remain soft.
10 - Allow cookies to cool on baking sheets for 5 minutes before transferring to a wire rack to cool completely.