This recipe deviates from the basic pie dough recipes with the goal being a flaky, tender, and flavorful crust that will roll out without cracking into ugly pieces, and it works. The first trick is to use butter and shortening at the fat in a 60:40 ratio. Butter for flakiness and flavor, shortening for a tender crust. It's not really a trick since a lot of recipes use both, but then many use just one or the other.
The second trick really is a trick. It was discovered by the folks at America's Test Kitchen back 2007. They were looking into a way to get the amount of water in the dough lower in order to minimize gluten activation which can make for a denser crust. The problem with using less water is that the dough becomes difficult to work with. One of the test team got the bright idea of replacing some of the water with alcohol which would provide liquid to help form and roll the dough, but evaporate during baking without activating the gluten. Vodka was chosen as an easily available and flavorless source of alcohol. Most vodkas are about half water so you are effectively cutting the amount of water by ¼.
2 ½ cups unbleached all-purpose flour, plus more for dusting the work surface
1 teaspoon salt
2 tablespoons sugar
½ cup vegetable shortening, chilled, cut into ¼-inch pieces
12 tablespoons (1 ½ sticks) cold unsalted butter, cut into ¼-inch pieces
¼ cup cold vodka
¼ cup ice water
Process the salt, sugar and 1 ½ cups of the flour in a food processor until combined, about 2 one-second pulses. Add the butter and shortening and process until the dough just starts to collect in uneven clumps, about 15 seconds (dough will resemble cottage cheese curds and there should be no uncoated flour). Scrape bowl with rubber spatula and redistribute dough evenly around processor blade. Add the remaining cup of flour and pulse until mixture is evenly distributed around the bowl and the mass of dough has been broken up, 4 to 6 quick pulses. Empty the mixture into a medium bowl.
Sprinkle all of the vodka and about half the water over mixture. With rubber spatula, use folding motion to mix, pressing down on dough until dough is slightly tacky and sticks together, if the dough seems to dry, add in the remaining water. Divide dough into two even balls and flatten each into 4-inch disk. Wrap each in plastic wrap and refrigerate at least 45 minutes or up to 2 days.