Place the flour, sugar, and salt in a food processor and pulse until combined.

Cut each stick of butter into about 10 chunks and add them to the food processor. Pulse until the butter is broken up and the mixture resembles coarse sand.

Scrape the bowl if needed, then pour the buttermilk over top of the flour mixture. Pulse again until the buttermilk is evenly distributed and a shaggy, crumbly dough begins to form. Alternatively, you can do this by hand, using a pastry cutter to work the butter into the dough, then making a well in the center, adding the buttermilk, and using a fork to moisten all the flour bits.

Turn the dough out onto a clean, lightly floured countertop. It's okay if it's still crumbly at this point. Divide the dough in half then gently use your hands to knead each half into a ball. If the dough remains dry and crumbly, add just a teaspoon or two more of buttermilk at a time until it comes together. Gently press down each ball into a disk. Wrap in saran wrap and chill for at least 1 hour or up to 3 days.

To roll, lightly sprinkle a countertop, silicone baking mat, or piece of parchment paper with flour. Place the chilled dough disk in the center and sprinkle with flour or top with a second layer of parchment.

Use a rolling pin to press the dough out, starting at the 12 o'clock position and moving to the 3 position. Rotate the dough clockwise and repeat until the dough is rolled into about a 12 inch round circle. Either wrap the dough around a rolling pin to transfer to the pie tin or peel off one layer of parchment, flip it into the pie tin, then peel off the second layer of parchment.

Cut off any excess around the edges and patch any bare spots. Crimp as you like then chill for 15 minutes before blind baking or filling and baking as directed.