Prepare the pie crust by mixing flour and salt.
Cut in the cold butter until the mixture resembles coarse crumbs.
Add ice water gradually until the dough comes together.
Chill the dough for at least 30 minutes.
Preheat the oven to 425°F (220°C).
Prepare the apple filling by mixing sliced apples with sugar, cinnamon, nutmeg, lemon juice, and flour.
Roll out the chilled pastry and line the pie pan.
Fill the pie crust with the apple mixture and dot with butter.
Roll out a second layer of pastry and place it over the filling.
Cut slits in the top to allow steam to escape.
Bake for 45-50 minutes until golden brown.
Cool before serving.