Whisk together flour and salt in large mixing bowl
Cut in cold butter using pastry cutter. Aim for butter to be pea sized or smaller and covered with flour.
Add sourdough discard or starter and vinegar.
Use bowl scraper to mix into a ball. If not coming together use ice water 1 T at a time to hydrate. Once dough comes together divide into 2 discs, wrap in plastic and refrigerate for 1-2 hours. I like to make bottom crust disc slightly larger than disc for the top. Roll out to form 12 inch discs about 1/4 inch thick and press bottom crust into greased pie plate or Dutch oven ( for pot pie). Add filling. Cover with top crust and score.
brush on egg wash prior to baking
Bake per filling recipe instructions