Preheat your oven to 325°F (163°C). Line a 9×13-inch glass or ceramic baking pan with parchment paper, leaving an overhang for easy removal.
In a mixing bowl, combine the melted butter, granulated sugar, vanilla extract, and salt. Gradually add 2 cups plus 2 tablespoons all-purpose flour and stir until fully combined into a dough. Press the dough firmly and evenly into the prepared pan.
Bake the crust for 20-22 minutes or until the edges are lightly browned. Remove from oven and gently poke holes in the crust surface with a fork (without piercing all the way through) to help the filling adhere. Set aside.
In a large bowl, whisk together sugar and flour until combined. Add eggs and freshly squeezed lemon juice and whisk thoroughly until smooth. For best results, bring eggs and lemon juice to room temperature before mixing. Sifting the flour and sugar beforehand can help avoid lumps.
Pour the lemon filling over the warm crust and return to the oven. Bake for 22-26 minutes or until the filling is set and no longer jiggles in the center.
Let the bars cool at room temperature for about 2 hours, then refrigerate for 1-2 hours until fully chilled.
Dust with confectioners’ sugar just before cutting into neat squares using a clean knife. Store leftovers covered in the refrigerator for up to one week.