Yield: 10-12 servings
Preheat the oven to 350°F.
For the crust, cream the butter and sugar until light. Next, combine the flour and salt in a separate bowl. Then add to the butter until just mixed. Place the dough onto a well-floured board and gather into a ball. Flatten the dough with floured hands and press it into a 7 inch by 11 inch pan building up a 1/2-inch edge on all sides. Chill the dough.
Bake the crust for 15 to 20 minutes, until very lightly browned. Let cool on a wire rack. Leave the oven on.
For the filling, whisk together the eggs, sugar, lemon zest, lemon juice, and flour. Pour over the crust and bake for 40 to 45 minutes, until the filling is set. Let cool to room temperature.
Cut into squares and dust with powdered sugar.