- Neutral-flavored cooking spray, such as canola oil, for pan
- 2¼ cups unsalted butter, at room temperature and softened
- ¾ cup confectioners' sugar
- 3½ cups flour
- 1 teaspoon kosher salt
Preheat oven to 400˚F.
Line a 17-by-13-inch rimmed baking sheet with parchment paper, then lightly spray the parchment with cooking spray.
In a stand mixer fitted with a paddle attachment, mix the butter and confectioners' sugar on high speed until light and fluffy, 3 to 5 minutes. Add the salt and mix for about 1 minute. With the mixer on low, add the flour, then gradually increase the speed to medium, pausing the mixer and scraping down the sides of the bowl as needed, until mixture is combined and smooth, 1 to 2 minutes.
Transfer the sticky dough to the center of the prepared baking sheet. To help spread out the dough, take a second sheet of parchment paper, lightly spray one side, then press the coated-side onto the mound of sticky dough. Using your hands, press through the parchment until the dough is evenly distributed from edge to edge of the baking sheet. Remove and discard the top sheet of parchment sheet.
With the tines of a fork, lightly poke holes from edge to edge of the dough.
Transfer the baking sheet to the oven and bake until light golden, about 15 minutes. Let cool, then slice into rectangles.