Transfer the apple mixture into the pie crust-lined dish. Place the second pie crust over the filling, trim the excess, and crimp the edges to seal. Cut slits in the top crust to allow steam to escape.
Brush the top crust with beaten egg. Bake in the preheated oven for 15 minutes. Reduce the temperature to 350°F and continue baking for another 45 minutes, or until the crust is golden brown and the filling is bubbly.