In a food processor combine flour, sugar and salt. Add butter and pulse into pea-sized pieces. Add water and pulse briefly, it will still look crumbly. Transfer the crumbs to 2 pieces of wax paper and form into 2 disks. Wrap with plastic wrap and chill overnight.
Roll out disks on a lightly floured workstation to 2" bigger than the 9" pie plate. Line the plate with one disk, and chill the other.
Preheat oven to 375 degree F.
Toss apple slices, sugar, cornstarch, lemon juice, vanilla, cinnamon, salt and nutmeg together. Transfer to pie shell and dot with butter. Brush edges of crust with water and place top crust on and pinch the edges together.
Slide pie into a brown paper bag and fold top down. Staple and bake for 1 hour.
Remove pie from oven and cut a large circle in the top of the bag and return to the oven to brown the crust. It should take approx 15-25 minutes.