01 - Preheat your oven to 350°F. Line a 9x13-inch baking pan with parchment paper, allowing a slight overhang for easy removal of the bars later.
02 - In a medium bowl, combine the melted butter, 1/2 cup sugar, 2 cups flour, and salt. Stir the mixture until a soft dough forms. Press the dough evenly into the bottom of the prepared pan.
03 - Place the pan in the oven and bake for 18 to 20 minutes, or until the crust is lightly golden. Remove from the oven but keep the crust in the pan.
04 - While the crust is baking, whisk together the 1 1/2 cups sugar and 1/4 cup flour in a separate bowl. Add the eggs, lemon juice, and lemon zest. Whisk until the mixture is smooth and fully combined.
05 - Pour the lemon filling directly over the hot pre-baked crust. Return the pan to the oven and bake for another 18 to 20 minutes, or until the center is set and only slightly jiggles when shaken.
06 - Let the bars cool completely in the pan set on a wire rack. Once cooled, use the parchment paper to lift them out of the pan. Slice into squares and dust generously with powdered sugar before serving.