Prepare the Crust: In a large bowl, whisk together the flour and salt. 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. Gradually add the ice water, 1 tablespoon at a time, mixing until the dough just comes together. Be careful not to overmix. Divide the dough in half, flatten each half into a disk, wrap in plastic wrap, and refrigerate for at least 30 minutes.

Prepare the Filling: In a large bowl, combine the sliced apples, granulated sugar, brown sugar, flour, cinnamon, nutmeg, and lemon juice. Toss gently to coat the apples evenly. Set aside.

Make the Streusel Topping: In a medium bowl, combine the flour, brown sugar, cinnamon, and salt. Add the cold butter pieces and use a pastry blender or your fingertips to cut the butter into the dry ingredients until the mixture forms coarse crumbs.

Assemble the Pie: Preheat your oven to 400°F (200°C). On a lightly floured surface, roll out one disk of dough into a 12-inch circle. Carefully transfer the dough to a 9-inch pie dish. Trim and crimp the edges as desired.

Pour the apple filling into the prepared crust. Sprinkle the streusel topping evenly over the apples.

Bake the Pie: Place the pie on a baking sheet (to catch any drips). Bake at 400°F (200°C) for 20 minutes. Reduce the oven temperature to 375°F (190°C) and continue baking for another 30-40 minutes, or until the crust is golden brown and the filling is bubbly. If the crust starts to brown too quickly, loosely tent the pie with aluminum foil.

Cool and Serve: Let the pie cool on a wire rack for at least 2-3 hours before slicing and serving. This allows the filling to set properly.