Preheat your oven to 350°F (175°C) and line a 9x13 inch baking pan with parchment paper, leaving an overhang on the sides for easy removal.

In a medium bowl, combine the flour, softened butter, and granulated sugar until a crumbly mixture forms, then press this mixture evenly into the bottom of the prepared pan.

Bake the crust for 15-20 minutes, or until lightly golden, then set aside to cool slightly while you prepare the filling.

In a large bowl, whisk together the granulated sugar and flour, then beat in the eggs, lemon juice, and lemon zest until the mixture is smooth and well combined.

Pour the lemon filling over the warm crust and return the pan to the oven for another 20-25 minutes, or until the filling is set and the edges are lightly browned.

Allow the lemon bars to cool completely in the pan on a wire rack before lifting them out by the parchment paper; this helps them set properly.

Once cooled, cut the bars into squares and dust generously with powdered sugar before serving.