01 - Preheat oven to 350°F. Line a 9x13-inch baking pan with parchment paper, leaving an overhang for easy removal.
02 - In a medium bowl, cream butter and sugar until light and fluffy. Add flour and salt, mixing until just combined. Press mixture evenly into the bottom of the prepared pan.
03 - Bake crust for 18 to 20 minutes until edges are lightly golden.
04 - While crust bakes, whisk sugar and flour in a large bowl. Add eggs, lemon juice, and lemon zest; whisk until smooth and fully combined.
05 - Pour lemon filling over hot crust. Return to oven and bake for 15 to 18 minutes until filling is set and slightly jiggly in the center.
06 - Remove from oven and cool completely in pan on a wire rack. Refrigerate at least 2 hours to ensure firm slicing.
07 - Lift bars from pan using parchment overhang. Dust generously with powdered sugar and cut into 16 squares.