01 - Preheat the oven to 350°F. Line two baking sheets with parchment paper.
02 - Whisk together the gluten-free flour blend, almond flour, and sea salt in a medium bowl; set aside.
03 - In a large bowl, cream the softened butter with light brown sugar and 1/4 cup powdered sugar until light and fluffy, approximately 2 minutes.
04 - Beat in the egg and vanilla extract until fully combined.
05 - Gradually fold the dry ingredients into the wet mixture until just incorporated.
06 - Scoop tablespoon-sized portions of dough, roll into balls, and place 2 inches apart on prepared baking sheets.
07 - Bake for 10 to 12 minutes, until edges are lightly golden and tops are set.
08 - Allow cookies to cool on baking sheets for 5 minutes, then transfer to a wire rack; dust generously with powdered sugar while still warm.
09 - Let cookies cool completely before serving.