apple pie recipe

1 pre-made pie crust (store-bought or homemade) 6 cups sliced and peeled apples (Granny Smith, Honeycrisp, or a mix) 3/4 cup granulated sugar 2 tablespoons all-purpose flour 1 teaspoon ground cinnamon 1/4 teaspoon ground nutmeg 1 tablespoon lemon juice 1 tablespoon unsalted butter, cut into small pieces 1 egg, beaten (for egg wash) 1 tablespoon granulated sugar (for sprinkling)