In the work bowl of a food processor, pulse together flour, sugar, and salt. Add butter and pulse until mixture is crumbly, about 1 minute.
Add buttermilk, 1 tablespoon at a time, stirring until a dough forms. Turn dough out onto a lightly floured surface; shape into two disks. Cover each tightly with plastic wrap; refrigerate until firm, approximately 2 hours.
Recipe by Victoria at https://victoriamag.com/peach-blackberry-pie-recipe/