Preheat oven to 425 degrees F.
Toss apple slices gently with sugar, flour, cinnamon and lemon juice. Spoon into unbaked pie shell. Top with crust, folding its edge under the top of the bottom crust. Crimp to seal. Bake at for 40 to 50 minutes, or until crust is golden brown.
Mix flour and salt. Cut in shortening until mixture resembles small peas.
Combine remaining ingredients and stir into shortening and flour. Let stand a few minutes.
Roll out dough on floured board.