Preheat oven to 400 degrees Fahrenheit. Line a baking sheet with parchment paper.
Remove the puff pastry from freezer to thaw while slicing peaches.
Wash and slice peaches in ¼ inch thick slices, making sure they are uniform in size.
Add all of the peach slices to a large bowl. Toss with cornstarch and cinnamon.
When puff pastry has thawed, slightly stretch pastry out on parchment paper.
Arrange the peach slices in a design on the center of the pastry leaving a 2 inch boarder.
Pull the pastry up around the peaches leaving the top exposed.
Sprinkle the sugar over the peaches, shaking the tray to allow the sugar to fall between the slices.
Add a teaspoon of water to egg white and stir well. Use a pastry brush to brush the edges of pastry. This will give it a golden brown shine.
Place in preheated oven and bake for 25 minutes or until puff pastry is golden brown and peaches are soft.
Allow to cool for 10 minutes before slicing. Add a scoop of vanilla ice cream or whipped cream.