01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together the gluten-free flour blend, baking soda, baking powder, and salt until evenly distributed. Set aside.
03 - In a large mixing bowl, beat the softened butter and granulated sugar with an electric mixer on medium speed until light and fluffy, approximately 2 to 3 minutes.
04 - Add the egg, lemon zest, lemon juice, and vanilla extract to the butter mixture. Beat until fully combined and smooth.
05 - Gradually add the dry ingredient mixture to the wet ingredients, mixing on low speed just until incorporated. Do not overmix.
06 - Using a spatula, gently fold the chopped cashews into the dough until evenly distributed.
07 - Scoop tablespoon-sized portions of dough and roll into balls. If desired, roll each ball in raw or turbinado sugar for a crunchy coating.
08 - Place dough balls 2 inches apart on the prepared baking sheets. Gently flatten each ball with your fingertips to about 1/2-inch thickness.
09 - Bake for 10 to 12 minutes, or until the edges are light golden and the centers appear just set. Rotate baking sheets halfway through for even browning.
10 - Allow cookies to rest on the baking sheets for 5 minutes, then transfer to a wire rack to cool completely before storing.