4 sticks (1 pound) unsalted butter, cut into tablespoons
3/4 cup ice water
1 large egg
1 tablespoon cider vinegar
How to Make It
In a food processor, pulse the flour with the salt. Add the butter and pulse until it is the size of large peas. Transfer the mixture to a large bowl and make a well in the center.
In a small bowl, lightly beat the ice water with the egg and vinegar. Add the liquid to the well and stir it into the butter-flour mixture. Using your hands, gather the dough and knead it in the bowl several times, until it is evenly moistened. Divide the pastry in half and flatten it into 2 disks. Wrap them with plastic and chill until firm.
The turnover pastry can be tightly wrapped in plastic and refrigerated overnight or frozen for up to 1 month.