1. Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
2. In a medium bowl, whisk together the flour, baking soda, and salt. Set aside.
3. In a large bowl, cream together the butter and sugar until light and fluffy, about 3-4 minutes. This step is crucial as it ensures the cookies have a tender crumb.
4. Add the egg, lemon zest, lemon juice, and vanilla extract to the butter mixture. Beat until well combined.
5. Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Be careful not to overmix, as this can lead to tougher cookies.
6. Using a tablespoon, scoop the dough and roll it into balls. Place them on the prepared baking sheet, spacing them about 2 inches apart.
7. Bake for 10-12 minutes, or until the edges are just starting to turn golden. Keep an eye on them to prevent over-baking.
8. Allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.

From my experience, these cookies are even better the next day, as the flavors have time to meld and intensify.