In the bowl of a stand mixer fitted with the paddle, cream the butter with the sugars at medium speed for 2 minutes.
With the mixer at low speed, beat in the sifted flour-and-salt mixture.
Preheat the oven to 350°F.
Line a 9- x 13-inch baking pan with parchment paper, allowing 2 inches of overhang on the two long sides.
Transfer the dough to the pan and press it over the bottom and 1 ¼ inches up the side all around.
(You can cover the dough with plastic wrap and press with the bottom of a measuring cup.)
Be sure the corners are not too thick.
Refrigerate until firm.
Bake the crust for 30 to 35 minutes, until golden brown; halfway through baking, use the back of a spoon to smooth the sides and corners of the crust.
Transfer the pan to a wire rack and let the crust cool before filling.
