In a large bowl, stir together the flour and salt.

Add the butter and blend with a pastry blender or your fingers until the mixture resembles a coarse meal.

Stir in the buttermilk with a spoon, then knead briefly until the mixture forms a dough. If it is very dry, you can add a bit of extra buttermilk, ½ teaspoon at a time, until it just comes together.

Shape the dough into a flattened disc, then wrap well in plastic wrap and refrigerate for at least 1 hour and up to 2 days. For longer storage, freeze for up to 2 months. Defrost overnight in the refrigerator.

When ready to use, roll the pastry out to ¼-inch (6-mm) thick on a floured surface and line a 9-inch (23-cm) pie dish with it.