In a medium mixing bowl, whisk all-purpose flour and salt. Using your hands, or a pastry cutter, mix the cold cubed butter into the flour until coarse, pea-sized crumbs.
Add ⅔ of the water and mix it. If the dough is still dry, add the rest of the water until the dough is moistened and can be shaped. Gently knead the dough until it comes together, shape it in the form of a disk and refrigerate for about an hour.
Preheat the oven to 400°F and line a baking sheet with parchment paper or a silicone baking mat. Set aside.
For the filling, pit and slice the peaches and mix them with granulated sugar and corn starch.
Roll the dough on a lightly floured surface until about ½ inch thick. Place the peaches in the middle in a circle, leaving 2-3 inches from the edges. Gently fold the edges of the dough over the peaches.
Brush the crust with egg wash and sprinkle granulated sugar over the top.
Bake it at 400°F for about 25-30 minutes, until the crust is beautiful golden brown color. Serve it warm with a scoop of ice cream on top. Enjoy!