Follow these steps to create an incredible Apple Pie With Puff Pastry:

1. Preheat the Oven: Preheat your oven to 425°F (220°C).
2. Prepare the Filling: In a large bowl, combine sliced apples, granulated sugar, lemon juice, cinnamon, nutmeg, flour, and salt. Toss until apples are evenly coated.
3. Roll Out the Pastry: On a lightly floured surface, roll out one sheet of puff pastry to fit your pie dish. Place it into the dish, allowing any excess to hang over the edges.
4. Fill the Pie: Pour the apple mixture into the pie crust. Distribute it evenly and dot the top with small pieces of butter.
5. Top with Pastry: Roll out the second sheet of puff pastry and place it over the filled pie. Trim the excess pastry and crimp the edges to seal.
6. Vent the Top: Cut several slits in the top crust to allow steam to escape during baking. You can create a decorative pattern if you wish.
7. Egg Wash: Brush the top crust with the beaten egg to achieve a golden finish after baking.
8. Bake the Pie: Place the pie in the preheated oven and bake for about 45-50 minutes, or until the crust is golden brown and the filling is bubbling.
9. Cool the Pie: Remove the pie from the oven and let it cool on a wire rack for 15-20 minutes before slicing.

These instructions will guide you through the process of creating a stunning and delicious pie with minimal stress.