To prepare the dough, combine the flour, sugar, and salt in a food processor and pulse a few times to blend. Add the butter and pulse until it is the size of small peas, about 15 times. With the processor running, add the ice water and process for about 10 seconds; stop the processor before the dough comes together. Turn the dough out onto a sheet of waxed paper, divide the dough in half, and shape it into two disks. Wrap them in plastic wrap and refrigerate for at least 1 hour. (The dough can be refrigerated for 2 days or frozen for up to 2 weeks; if it has been frozen, defrost the dough for 30 minutes at room temperature.)

Preheat the oven to 450°F.

Roll one disk of dough into an 11-inch circle on a lightly floured surface. Transfer to a baking sheet. (Reserve the second disk of dough for another use.)

To prepare the filling, combine the flour and sugar in a small bowl. Blend in the butter with two knives until the mixture resembles coarse meal.

Place the peaches in the center of the dough circle on the baking sheet and top with the butter-sugar mixture. Begin draping the edges up and over, forming about 3 pleats. Crimp the pleats and press down to seal. Brush the pastry with the egg wash and sprinkle with the sugar.

Bake the tart for about 25 minutes, or until golden brown. Let cool on a rack and serve slices with vanilla ice cream or crème anglaise.

Variation: Line the dough bottom of the crostata with a heaping tablespoon of pecan frangipane before adding the peaches. To make the frangipane, combine ½ cup toasted pecans and ½ cup sugar in a food processor and process until the nuts are coarsely ground. Add 8 tablespoons (1 stick) of unsalted butter, cut into small pieces, and 1 large egg and pulse until the mixture resembles a coarse paste.