Cut peaches in half and remove the pit. Slice each half into ¼-inch to ½-inch thick slices.
In a large bowl, add sliced peaches, sugar, cornstarch, cinnamon and pinch of salt. Toss to combine.
Remove dough from the refrigerator and arrange peaches (not the juices) in a concentric pattern starting in the center and working your way out. Leave about a 2 to 3 inch border of dough around the edges.
Fold the border over the filling, pleating the edge to make it fit. The center will be open. Brush crust with egg wash and sprinkle with sugar.
Bake galette at 400 degrees F for 30 to 40 minutes or until the crust is golden brown. Let the galette cool for about 10 minutes before serving warm.
Notes
Pastry dough: I use my homemade pie dough and save the other half for another recipe. You can also use one store-bought pie crust if you prefer.Store covered in the refrigerator for up to 2 days.Freeze peach galette wrapped in plastic wrap and aluminum foil for up to 1 month. Reheat the frozen galette for 15 minutes at 350 F.