In a medium bowl, whisk together the all-purpose flour, baking soda, and salt. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment, cream together the softened unsalted butter and granulated sugar on medium speed until light and fluffy, about 2-3 minutes. Scrape down the sides of the bowl as needed.

Beat in the large egg until just combined. Stir in the vanilla extract, fresh lemon zest, and fresh lemon juice until well incorporated. The mixture may look slightly curdled, which is normal.

Gradually add the dry ingredient mixture to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix; overmixing can lead to tough cookies. The dough will be soft and sticky.

Cover the bowl with plastic wrap and refrigerate the dough for at least 30 minutes, or up to 1 hour. Chilling is crucial for the cookies to hold their shape and develop a chewy texture.

While the dough chills, preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper.

Place the powdered sugar in a shallow bowl. Scoop out dough in tablespoon-sized portions (about 1.5-2 tablespoons per cookie) and roll them into balls. Generously roll each dough ball in the powdered sugar until fully coated.

Arrange the coated dough balls on the prepared baking sheets, leaving about 2 inches between each cookie. Bake for 10-12 minutes, or until the edges are lightly golden and the centers are just set but still look soft. Do not overbake to ensure a chewy texture.

Let the cookies cool on the baking sheets for 5 minutes before transferring them to a wire cooling rack to cool completely.