01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together almond flour, gluten-free all-purpose flour, baking powder, sea salt, and sugar until well blended.
03 - In a large bowl, beat softened butter with a hand mixer until creamy, about 1 minute. Add egg, lemon zest, lemon juice, vanilla extract, and almond extract. Beat until uniformly combined.
04 - Gradually mix the dry ingredient blend into the wet mixture until a soft dough forms.
05 - Scoop tablespoon-sized portions of dough, roll each into balls, and coat in additional granulated sugar.
06 - Position dough balls 2 inches apart on prepared baking sheets. Gently flatten each with your palm or the base of a glass.
07 - Bake in preheated oven for 11 to 13 minutes, until cookie edges are lightly golden.
08 - Rest cookies on baking sheet for 5 minutes, then transfer to a wire rack to finish cooling entirely.