Preheat the oven to 350 degrees F.
Mix sliced apples with sugar, cinnamon, flour, and nutmeg. Place 1 of the pie crusts into a 9-inch pie plate. Place the apple mixture into the piecrust and cover with a crust top. Add butter into apples, if desired. Combine the egg and water and beat to make an egg glaze. Brush the top crust with the egg glaze for a nice glossy appearance. Bake in the oven for 50 to 55 minutes. Make sure to place pie on a tray to prevent juices from spilling into the oven.
Test pie with a sharp knife to feel if apples are tender enough for your taste. If necessary cook pie for 5 minutes more and test again. Repeat process if desired.
Cool and serve with ice cream or any of your favorite toppings.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.