Make the Cookies:

1. Preheat the oven to 350°F (175°C). Line baking sheets with parchment paper.
2. In a large bowl, cream the butter and sugar together until light and fluffy. Add the egg, lemon juice, lemon zest, and vanilla extract, mixing until well combined.
3. In a separate bowl, whisk together the flour, baking powder, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
4. Scoop 1.5-tablespoon portions of dough and roll into balls. Place on the prepared baking sheets, spacing them about 2 inches apart. Flatten slightly with the palm of your hand.
5. Bake for 10–12 minutes, or until the edges are set and the cookies are lightly golden. Allow the cookies to cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.

Make the Glaze:

1. In a small bowl, whisk together the powdered sugar, lemon juice, and lemon zest until smooth. Adjust the consistency by adding more powdered sugar for thickness or more lemon juice for a thinner glaze.

Glaze the Cookies:

1. Once the cookies are completely cooled, spoon or drizzle the glaze over the tops. Let the glaze set for 15–20 minutes before serving.