01 - Preheat oven to 350°F. Line two baking sheets with parchment paper and set aside.
02 - In a large mixing bowl, whisk together the almond flour, gluten-free flour blend, granulated sugar, salt, baking powder, and lemon zest until evenly distributed.
03 - In a separate bowl, beat the egg with vanilla extract, melted butter, and lemon juice until smooth and well combined.
04 - Pour the wet mixture into the dry ingredients and stir with a spatula until a soft, cohesive dough forms. Do not overmix.
05 - Scoop tablespoon-sized portions of dough and roll into balls. Arrange on the prepared baking sheets, spacing them about 2 inches apart. Gently flatten each ball with your palm or the bottom of a glass.
06 - Bake for 10 to 12 minutes, or until the edges are lightly golden. Let the cookies rest on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.
07 - In a small bowl, whisk together the powdered sugar, lemon juice, and almond extract. Add water one teaspoon at a time until the glaze reaches a thick but pourable consistency.
08 - Drizzle the glaze over the cooled cookies. Allow the glaze to set for 10 to 15 minutes before serving.