Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.
In a small bowl, whisk together the flour, salt, and baking powder, then set aside. In another small bowl, mix the lemon zest and sugar together with your fingers until the sugar is infused with the lemon's fragrance.
2¼ cups all-purpose flour, ½ teaspoon salt, ½ teaspoon baking powder, 2 teablespoon lemon zest, ¾ cup sugar
In a stand mixer, beat the butter and lemon sugar until it's light and fluffy. Add in the vanilla extract, lemon juice, and egg, and continue mixing until everything is well combined. On low speed, gradually add in the flour mixture until the dough just comes together.
1 cup unsalted butter, 1 teaspoon vanilla extract, 1 tablespoon lemon juice, 1 large egg
Scoop out the cookie dough by the tablespoon and place it on the prepared baking sheets, leaving space between them as they will spread. Using the palm of your hand gently press down on the cookie dough.
Scoop out tablespoons of dough onto the baking sheets, leaving space between each cookie. Gently press each dough ball down with your palm to slightly flatten them. Bake for 11 to 14 minutes, until the edges are lightly golden. Let the cookies cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.