Preheat your oven to 425°F (220°C).
Prepare the pie crust if making from scratch, or roll out the store-bought crust.
Peel, core, and slice the apples into thin slices, then place them in a large bowl.
Add lemon juice, sugar, flour, cinnamon, nutmeg, and salt to the apples and toss to coat evenly.
Pour the apple mixture into the bottom crust and dot with small pieces of butter.
Cover with the top crust, sealing the edges by crimping. Cut slits to allow steam to escape.
Brush the top crust with egg wash and sprinkle sugar if desired.
Bake in the preheated oven for 15 minutes at 425°F, then reduce the temperature to 350°F (175°C) and bake for an additional 30-40 minutes.
Remove from the oven and let cool on a wire rack.
Slice and serve your pie warm or at room temperature, maybe with vanilla ice cream.