How to Make It
Preheat the oven to 375° and position a rack in the lower third. In a bowl, toss the peaches and raspberries with the 3/4 cup of sugar, the cornstarch and the salt.
Roll out the larger piece of Flaky Pie Dough to a 13-inch round, about 1/8 inch thick. Line a 9 1/2-by-1 3/4-inch glass pie plate with the dough. Brush the overhang with water and spoon in the filling.
Roll out the smaller piece of dough to a 12-inch round and lay it over the filling; press the edges together. Trim the overhang to 1/2 inch, fold it under itself and crimp. Lightly brush the top with water and sprinkle with sugar. Cut a few slits for steam to escape.
Bake the pie until the filling is bubbling and the crust is golden brown, about 2 to 2 1/4 hours. Cover the edge of the pie with foil if it begins to darken. Let cool for 5 hours at room temperature before serving.