Step 1: Prepare the Pie Crust

1. In a large bowl, combine the flour and salt. Cut in the butter using a pastry cutter or fork until the mixture resembles coarse crumbs.
2. Gradually add ice water, 1 tablespoon at a time, mixing until the dough comes together. Shape into a disk, wrap in plastic wrap, and refrigerate for at least 30 minutes.
3. Roll out the chilled dough on a floured surface into a 12-inch circle. Transfer it to a 9-inch pie dish, trim the edges, and flute as desired.

Step 2: Make the Apple Filling

1. Preheat the oven to 375°F (190°C).
2. In a large bowl, toss the sliced apples with granulated sugar, brown sugar, cinnamon, nutmeg, flour, and lemon juice until evenly coated.

Step 3: Prepare the Streusel Topping

1. In a medium bowl, combine the flour, granulated sugar, and brown sugar. Cut in the butter using a pastry cutter or fork until the mixture forms pea-sized crumbs.
2. Stir in the chopped nuts, if using.

Step 4: Assemble the Pie

1. Fill the prepared pie crust with the apple filling, spreading it evenly.
2. Sprinkle the streusel topping over the apples, covering them completely.

Step 5: Bake the Pie

1. Place the pie on a baking sheet to catch any drips and bake for 45–55 minutes, or until the topping is golden brown and the filling is bubbly.
2. If the crust edges brown too quickly, cover them with aluminum foil or a pie shield halfway through baking.

Step 6: Cool and Serve

1. Let the pie cool for at least 2 hours to allow the filling to set.
2. Serve warm or at room temperature, optionally topped with vanilla ice cream or whipped cream.