Preparing the crust: In a large bowl, combine the flour, sugar, and salt. Add the cold butter cubes and cut into the flour until the mixture resembles coarse crumbs. Gradually add ice water, one tablespoon at a time, and mix until the dough just comes together. Split the dough into two parts, wrap in plastic, and refrigerate for at least 1 hour.

1. Preparing the filling: Peel, core, and slice the apples. Toss the apple slices with granulated sugar, brown sugar, cinnamon, nutmeg, flour, and lemon juice. Let it sit for 10 minutes.
2. Assembling the pie: Roll out one disk of dough on a floured surface and fit it into a 10-inch cast iron skillet. Pour the apple filling into the crust, dot with butter. Roll out the second disk and cover the pie. Trim and crimp the edges, then cut slits in the top or create a lattice pattern.
3. Baking the pie: Preheat the oven to 375°F (190°C). Bake the pie for 45-50 minutes, or until golden brown. Let it cool for 1 hour before serving.