Step 1
Butter one 9x13x2 baking pan and line with parchment paper.
Step 2
Prepare the crust. Beat butter and sugar until smooth. In a small bowl, combine flour and salt. Add to butter mixture and beat at low speed until just combined.
Step 3
Transfer the dough to the prepared pan and press evenly into the bottom of the pan. Use the back of a measuring cup for an even crust. Place the crust in the refrigerator for 30 minutes. Preheat oven to 350°F.
Step 4
Remove the crust from the refrigerator and bake for 15-20 minutes, until slightly golden. Reduce oven temperature to 300°F.
Step 5
While the crust is baking, prepare the filling. In a medium bowl whisk together flour and sugar. In a large bowl whisk together eggs, egg yolk, lemon juice, lemon zest, and salt. Combine both mixtures and pour over crust.
Step 6
Bake bars for 25-30 minutes until center is set. Let bars cool completely. Cover with plastic wrap and refrigerate until chill. Using a sharp knife cut into 2x3-inch bars. Dust with powder sugar before serving.
