Preheat the oven to 350 degrees. Line 2 baking sheets with parchment paper and set aside.

In a medium bowl, whisk the flour, almond flour, baking powder, and salt until combined.

In a large bowl, beat the butter with 1 cup of the powdered sugar and lemon zest at medium low speed with a hand mixer until incorporated, then increase the speed to medium high and cream until light and fluffy, about 2 minutes. Add the egg yolk and lemon juice and beat until incorporated.

Add the dry ingredients to the butter mixture and beat on low just until the dough starts to come together — it will still be in clumps. Knead the dough together with your hands in the bowl, and form the dough into 1″ balls.

Place on the prepared baking sheets 1″ apart and bake for 18-20 minutes, rotating halfway between baking, until the bottoms are golden brown. Remove from heat and cool on a wire rack for 5-10 minutes.

Place the remaining 2 cups of powdered sugar in a medium bowl. Roll the cookies a few at a time in the powdered sugar and place on the wire rack to cool completely.

Once cooled, cookies may be stored in an airtight container for up to 2 weeks. Enjoy!