Preheat the oven to 400F.

In a large bowl, toss together the peaches, sugar, cinnamon and tapioca and set aside for 10 minutes.

Place the rolled pie crust into the bottom of the pie pan. Pour the peach mixture into the bottom crust. Top with the 2nd crust and crimp the edges decoratively. Cut slits in the top to vent.

Beat the egg with 1 T water. Brush the pastry crust with the egg, then sprinkle liberally with the sugar (optional).

Place the pie on a cookie sheet in the preheated oven. Bake for 20 minutes. Reduce the oven temperature to 350 and bake for an additional 40 minutes.

Remove from oven and allow to cool to warm before cutting and serving.