Whisk flour and salt together in a large bowl, cut the butter into 1/2-inch cubes, and add the apple cider vinegar to the ice water.

Working quickly, add the butter to the flour and toss to coat. Then use your fingers or the palms of your hands to press each cube of butter into a flat sheet. Keep tossing the butter in the flour as you go to ensure that each butter piece is coated with flour. The idea is to create flat, thin shards of butter that range form about the size of a dime to about the size of a quarter.

If at any time the butter seems warm or soft, briefly refrigerate the bowl.

Sprinkle about 4 tablespoons of the icy cold vinegar-water mixture over the flour mixture. Use a gentle hand or wooden spoon to stir the water into the flour until just combined. If the dough seems dry, add more water a couple of teaspoons at a time. You have added enough water when you can pick up a handful of the dough and easily squeeze it together without it falling apart.

Press the dough together. Form each into a disk, and wrap in plastic wrap. Chill the dough for at least 2 hours before using but preferably overnight. Keeps for up to three months in the freezer wrapped in a double layer of plastic wrap and a layer of foil. Thaw in refrigerator before using.