2 3/4 cups all-purpose flour
2 tablespoons cornstarch
1/2 teaspoon salt
18 tablespoons unsalted butter, chilled
1 tablespoon apple cider vinegar
1/2 cup ice water
Cut the butter into 1 inch cubes, put into freezer.
Whisk together the flour, cornstarch and salt in a large bowl.
Add the butter and coat with flour. Using a pastry cutter, work the butter into the flour. Continue until the butter is mostly broken up, some pieces the size of marbles might remain.
Add the vinegar to the water, and then pour half into the dough. Toss it together. Pour in the other half and begin mixxing together. The dough should easily squeeze together in your hands.
Empty the dough on a work surface and divide into two pieces.
Place in plastic wrap and then flatten to about 1/2 inch, using a rolling pin if you want.
Refrigerate for at least 2 hours, but preferably overnight.