Yield 40 cookies
4 cups all-purpose flour, plus more for flouring your work surface and hands
1¼ cups vegetable shortening (such as Crisco)
1¼ cups (2½ sticks) unsalted butter
1 cup powdered (10X) sugar
4 extra large eggs
¼ teaspoon salt
½ cup cold water
1 Put flour, shortening, butter, sugar, eggs and salt in bowl of a stand mixer fit with the paddle attachment. (You can use a hand mixer if you allow the butter and shortening to soften at room temperature before beginning).
2 Paddle at low speed until mixture resembles creamy cookie dough, about 3 minutes. It should be tacky and not run down side of the paddle when the motor is stopped. With the motor running on low, slowly add the water and mix until fully absorbed, about 2 minutes more.
3 Wrap the dough in plastic wrap and chill in refrigerator for 1 hour or up to 3 days, but do not freeze. Remove dough from refrigerator and let it come to room temperature before proceeding.
4 Position a rack in the center of the oven and preheat to 325 degrees.
5 This is very sticky, difficult dough to handle so you have to generously flour your work surface and your hands. After flouring, transfer half the dough to your surface and gently roll it into a log, reflouring the top of the dough as necessary as you work to keep it manageable. Work the dough into a 12-inch square, inch thick.