Combine flour sugar and salt together in a large bowl. It's best to use a food processor for this.
Add in the cold butter to the mixture and pulse it together until smooth. Make sure all the butter is incorporated into the flour. Mixture will be very flaky.
Pour flour mixture into mixing bowl and place in the freezer for 15 minutes to completely chill the butter.
Remove mixture from freezer and add in the buttermilk. Use a spoon to mix together and then your hands.
If your mixture is too dry, you can add in a tablespoon or two of water.
On a lightly floured surface, divide the pie crust dough into two and then flatten each into a disk with a rolling pin.
Wrap each disk with plastic wrap and place in fridge until ready to use.
Or place wrapped pie dough into freezer bags in the freezer for up to a year until ready to use.