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. Gradually add the ice water, one 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 disc, wrap in plastic wrap, and refrigerate for at least 30 minutes or up to 2 hours. This allows the gluten to relax.

In a large bowl, combine the sliced apples, granulated sugar, flour, cinnamon, nutmeg, and allspice (if using). Toss to coat evenly, then stir in the lemon juice.

Preheat your oven to 375°F (190°C).

On a lightly floured surface, roll out one disc of dough into a 12-inch circle. Gently transfer the dough to a 9-inch pie plate, pressing it into the bottom and up the sides. Trim any excess dough and crimp the edges.

Pour the apple filling into the prepared pie crust. Dot the top with small pieces of butter.

Roll out the remaining disc of dough into a 12-inch circle. Gently place it over the apple filling. Trim any excess dough and crimp the edges to seal. Alternatively, create a lattice top by cutting the dough into strips and weaving them over the filling.

In a small bowl, whisk together the egg and milk or water. Brush the top of the pie crust with the egg wash for a shiny, golden-brown finish (optional).

Cut a few slits in the top crust to allow steam to escape during baking.

Bake for 45-55 minutes, or until the crust is golden brown and the filling is bubbling. If the crust starts to brown too quickly, loosely cover the pie with aluminum foil.

Let the pie cool on a wire rack for at least 2 hours before slicing and serving.