Step 1

Make the crust:

Step 2

Preheat the oven to 350 F.

Step 3

In the bowl of an electric mixer fitted with the paddle attachment, cream the butter and sugar until light.

Step 4

Combine the flour and salt, and with the mixer on low, add to the butter until just mixed.

Step 5

Dump the dough onto a well-floured board and gather into a ball. Flatten the dough with floured hands and press it into a 9- by 13-inch baking sheet, building up a 1/2-inch edge on all sides. Chill.

Step 6

Bake the crust for 15 to 20 minutes, until very lightly browned. Let cool on a wire rack. Leave the oven on.

Step 7

Make the filling:

Step 8

Whisk together the eggs, sugar, lemon zest and juice, and flour.

Step 9

Pour the mixture over the crust and bake for 30 to 35 minutes, until the filling is set. Let cool to room temperature.

Step 10

Cut into triangles and dust with powdered sugar.