Gather all ingredients. Preheat your oven to 450°F (230°C).

On a lightly floured surface, roll out one pastry disk and line a 9-inch pie plate.

In a large bowl, toss sliced apples with sugar, flour, cinnamon, nutmeg, and lemon juice until evenly coated.

Pour the apple mixture into the prepared crust, then dot with butter pieces.

Roll out the second pastry disk, place over the apples, and crimp the edges to seal.

In a small bowl, whisk together egg and water. Brush the top crust and sprinkle with coarse sugar.

Cut 4–5 slits in the top crust to vent steam.

Bake at 450°F for 15 minutes. Without opening the oven, reduce heat to 375°F (190°C) and bake an additional 35–40 minutes or until the crust is golden and filling is bubbly.

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