Preheat the oven to 375°F. Line two baking sheets with parchment paper or silicone baking mat (or lightly grease with non-sticking cooking spray).
In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
In a large bowl using an electric mixer, cream together butter and sugar until light and fluffy, about 2 to 3 minutes.
Add egg and beat to combine. Add vanilla, lemon juice, and lemon zest. Beat to combine. Scrape down bowl as needed.
Add flour mixture, and mix at low to medium speed just until no flour streaks remain.
Using a cookie scoop, or tablespoon to portion into 1 ½ inch balls. Place on prepared baking sheets, leaving about 2 inches between them.
Bake for 10 to 12 minutes. The edges will look done, but the center will still look slightly soft. Remove from the oven and cool on the baking sheets for 5 minutes before transferring to a wire rack to finish cooling completely.
In a small mixing bowl, combine icing ingredients. With an offset spatula, ice the top of each cookie. Adjust consistency if needed.
