Make the Pie Crust:
1. In a large bowl, whisk together the flour and salt.
2. Cut in the cold butter using a pastry blender or your fingertips until the mixture resembles coarse crumbs with some pea-sized pieces of butter remaining. Alternatively, pulse in a food processor until just combined.
3. Gradually add the ice water, 1 tablespoon at a time, mixing until the dough just comes together. Be careful not to overmix.
4. Divide the dough in half, flatten each half into a disk, wrap in plastic wrap, and refrigerate for at least 30 minutes.

Prepare the Apple Filling:
1. In a large bowl, combine the sliced apples, granulated sugar, 2 tablespoons flour, cinnamon, nutmeg, salt, and lemon juice. Toss gently until the apples are evenly coated.

Assemble the Pie:
1. Preheat your oven to 425°F (220°C).
2. On a lightly floured surface, roll out one disk of dough into a 12-inch circle.
3. Carefully transfer the dough to a 9-inch pie plate, gently pressing it into the bottom and up the sides.
4. Pour the apple filling into the crust-lined pie plate.
5. Dot the top of the filling with the small pieces of butter.
6. Roll out the second disk of dough. Place it over the filling.
7. Trim and crimp the edges of the pie crust to seal.
8. Cut several slits in the top crust to allow steam to escape.
9. Brush the top crust with the beaten egg wash.
10. Sprinkle with turbinado sugar, if desired.

Bake the Pie:
1. Place the pie on a baking sheet to catch any drips.
2. Bake for 15 minutes at 425°F (220°C).
3. Reduce the oven temperature to 375°F (190°C) and continue baking for another 35-45 minutes, or until the crust is golden brown and the filling is bubbly.
4. If the crust starts browning too quickly, loosely tent it with aluminum foil.
5. Let the pie cool on a wire rack for at least 2-3 hours before slicing and serving to allow the filling to set.