01 - Preheat oven to 350°F. Line a 9x13-inch baking pan with parchment paper, leaving an overhang on the sides for easy removal.
02 - In a medium bowl, cream together the softened butter and sugar until light and fluffy. Add the flour and salt, then mix until a crumbly dough forms.
03 - Press the dough evenly into the bottom of the prepared pan. Bake for 18 to 20 minutes or until the edges are lightly golden.
04 - While the crust bakes, whisk together the eggs and sugar in a separate bowl until well blended. Add the flour and whisk until smooth, then stir in the fresh lemon juice and zest.
05 - Remove the crust from the oven and reduce the temperature to 325°F. Pour the lemon filling evenly over the hot crust. Return to the oven and bake for 18 to 20 minutes, or until the center is set and no longer jiggles when gently shaken.
06 - Cool completely in the pan on a wire rack. Use the parchment overhang to lift the bars out, then cut into 12 squares. Dust with powdered sugar before serving.