Preheat oven to 450° F. Position one oven rack on the bottom and one in the center.
Remove dough from the refrigerator.
On a lightly floured surface, roll out one dough disk to 1/4-inch thick.
Transfer the dough to a pie plate and gently press it into the plate, leaving any excess dough hanging over the edge for crimping later.
Place sliced peaches in a large bowl. Sprinkle with lemon juice.
In a small bowl, mix flour, cinnamon, and sugar. Add mixture to peach bowl and gently combine.
Spoon the peach mixture into the prepared bottom crust, and top evenly with diced butter.
On a lightly floured surface, roll out the other dough disk to 1/4-inch thick.
Use the dough to cover the pie, tuck edges under the bottom piecrust, and crimp to seal.
If you're adding extra dough decoration, add it now. Roll out the extra dough on a floured surface. Using a knife, cut out leaves, flowers, or whatever tickles your fancy. Add the dough decoration to the top of the pie.
Whisk egg together with cold water to make an egg wash. Brush it over the top of the pie.
Place pie in center of the oven. Bake for 10 minutes before reducing the oven temperature to 350° F. Bake for approximately 40 minutes or until the crust is golden brown.
Serve with vanilla ice cream or whipped cream.