In a mixing bowl, combine sugar, cinnamon, flour, nutmeg (or apple pie spice), and salt; mix thoroughly. Pour the spice mix over the apples and stir until the apples are coated.
Line one crust in a 9 inch deep dish pie pan. Place the apples in the pie crust. Dot the apple filling evenly with butter. Fit the top crust over the apples. Press the crust down gently and cut 3 or 4 slits in the top crust to allow steam to escape while the pie bakes
Bake in the preheated oven 50 minutes, or until the crust is golden brown. Check the pie after the first 30 minutes of cooking: if the crust is already browned reduce the heat to 350 degrees F (175 degrees C) to allow the apples to cook without the crust burning.