01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, and salt until well blended.
03 - In a large bowl, beat softened butter and granulated sugar with an electric mixer until light and fluffy, approximately 2-3 minutes.
04 - Beat in eggs one at a time, ensuring each is fully incorporated. Mix in lemon juice, lemon zest, and vanilla extract until combined.
05 - Gradually add the flour mixture to the wet ingredients, mixing on low speed just until the dough comes together. Avoid overmixing.
06 - Drop rounded tablespoons of dough onto the prepared baking sheets, leaving 2 inches of space between each cookie to allow for spreading.
07 - Bake for 10-12 minutes until the edges are lightly golden. The centers should appear slightly underbaked for optimal texture.
08 - Let cookies rest on the baking sheets for 5 minutes to set, then transfer to a wire rack to cool completely before frosting.
09 - Whisk together sifted powdered sugar, lemon juice, lemon zest, and melted butter until smooth and spreadable. Adjust consistency with additional lemon juice if needed.
10 - Spread a thin layer of lemon frosting over each cooled cookie. Allow the frosting to set for approximately 15 minutes before serving or storing.