01 - Preheat the oven to 350°F. Line two baking sheets with parchment paper and set aside.
02 - In a medium bowl, whisk together the gluten-free flour blend, baking soda, baking powder, and fine sea salt until evenly distributed.
03 - In a large bowl, beat the softened butter with light brown sugar and granulated sugar using a hand mixer or stand mixer on medium speed until pale, light, and fluffy, approximately 2 minutes.
04 - Add the egg and vanilla extract to the butter mixture, beating until fully incorporated and the mixture is smooth.
05 - Gradually add the dry ingredient mixture to the wet ingredients, mixing on low speed until just combined. Avoid overmixing to maintain a tender texture.
06 - Using a spatula, gently fold the dark chocolate chips and roasted cashew pieces into the dough until evenly distributed.
07 - Scoop heaping tablespoons of dough onto the prepared baking sheets, spacing each portion approximately 2 inches apart to allow for spreading.
08 - Bake for 10 to 12 minutes, or until the edges are golden brown and the centers appear just set. For extra crispiness, extend baking time by 1 to 2 minutes.
09 - Allow the cookies to cool on the baking sheets for 5 minutes, then transfer to a wire rack to cool completely before serving.