Preheat your oven to 350°F (175°C).

Measure out all your ingredients and ensure your butter is softened.

In a medium bowl, whisk together the almond flour, coconut flour, baking soda, and salt.

In a separate large mixing bowl, cream the softened butter and granulated sugar together using an electric mixer for 2-3 minutes until light and fluffy.

Add the egg, lemon juice, lemon zest, and vanilla extract to the butter mixture and mix until well combined.

Gradually add the dry ingredients to the wet mixture and stir until a soft, slightly sticky dough forms.

Scoop tablespoon-sized portions of dough, roll them into balls, and place them on a prepared baking sheet, spaced about 2 inches apart.

Gently flatten each cookie with the palm of your hand.

Bake the cookies for 10-12 minutes until the edges are lightly golden.

Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.

Dust with powdered sugar before serving, if desired.