In the work bowl of a food processor, pulse together flour, sugar, and salt. Add cold butter; pulse until mixture is crumbly. With processor running, add buttermilk in a slow, steady stream just until dough comes together.
Turn out dough onto a lightly floured surface, and shape into a disk. Wrap in plastic wrap, and refrigerate for at least 1 hour or up to 2 days. Let dough stand at room temperature until slightly softened, about 15 minutes, before rolling.
Recipe by Paula Deen Magazine at https://pauladeenmagazine.com/caramel-apple-slab-pie/