Steam the apple slices in 1 or 2 Tbsp water in a covered saucepan for 5 minutes. Remove from heat and add the sugars, salt, flour, nutmeg, cinnamon, lemon juice, and butter. Mix well and turn into unbaked pie shell.
Blend sugar, flour and butter. Sprinkle on top of pie. Sprinkle nuts over topping.
Cover top of pie with foil and bake at 425 for 15 minutes, then reduce oven heat to 375. Remove foil and bake 30 to 40 minutes.