To make the filling:
Preheat oven to 450. Peel, core and slice 6 cups apples. Combine apples with brown sugar, flour, cinnamon, and salt.
To roll out the crust:
Generously flour two overlapping sheets of wax paper with pastry flour (try Gleason's Grains as a local choice) and also flour the rolling pin. Roll out first disk into 13" round, fit into a 9" pie plate, and refrigerate. Roll second disk into 12" round and set aside.
Stir filling and pour into bottom crust. Dot with butter. Brush edge of the bottom crust with cold water. Cover with top crust and seal and crimp the edge. Cut steam vents.
Bake for 15 min. Turn heat down to 350, lightly cover with foil, and bake for +/- 1 hour or until filling bubbles.
See our Heirloom Apple Guide for notes on which apple varieties to use.