I can think of (ahem) several good uses for vodka, and foolproof pie crust is definitely not one of them.
Yet, according to Cooks Illustrated, the inclusion of this liquid is the ticket to the most moist, flaky pie crust you've ever tasted. Apparently, vodka adds extra moistness to the dough (so be sure to chill it for a long time before rolling it out so it's easier to work with), but then evaporates in the baking process.
At this point in prime of pie season with Thanksgiving just around the corner, I'm willing to try anything! I'm posting the recipe here, and Smitten Kitchen has a helpful step-by-step guide to this recipe (including photos).
What's your secret to foolproof pie crust?
2 1/2 cups (12 1/2 ounces) unbleached all-purpose flour
1 teaspoon table salt
2 tablespoons sugar
12 tablespoons (1 1/2 sticks) cold unsalted butter, cut into 1/4-inch slices
1/2 cup cold vegetable shortening, cut into 4 pieces
1/4 cup cold vodka
1/4 cup cold water
1. Process 1 1/2 cups flour, salt, and sugar in food processor until combined, about 2 one-second pulses. Add butter and shortening and process until homogeneous 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 remaining cup flour and pulse until mixture is evenly distributed around bowl and mass of dough has been broken up, 4 to 6 quick pulses. Empty mixture into medium bowl.
2. Sprinkle vodka and water over mixture. With rubber spatula, use folding motion to mix, pressing down on dough until dough is slightly tacky and sticks together. 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.