For the crust: In large bowl, stir flour and salt together. Using a pastry blender or fork, cut butter and shortening into flour until mixture resembles cornmeal. Add 8 tablespoons cold water and stir until mixture holds together in large clumps. Add additional water tablespoon by tablespoon if the dough is still dry. Divide dough into two discs, cover with plastic wrap and chill at least 1 hour.
Once pie crust is chilled, roll each disc into a 14 in. circle, about 1/8 in. thick. Place in pie pans, pressing firmly into the sides and bottom of the pan.
For the filling: In a large bowl, combine sugar, flour and cinnamon. Add sliced and skinned apples to bowl and mix well to coat with mixture.
For the topping: Combine walnuts, flour, oats, sugar, cinnamon and butter until crumbly.
Pour filling into each prepared crust. Sprinkle both evenly with topping.
Bake 35-40 minutes or until filling is bubbly and streusel is crisp. If needed, cover pie loosely with aluminum foil during last 10 minutes to avoid overbrowning.
Cool pies in pans on cooling rack at least 1 hour before serving.