Prepare the pie pastry and let it rest overnight, if possible.

Preheat the oven to 425ºF and place an oven rack in the lowest and middle parts of the oven.

Roll out the pastry: Roll out 1 pie pastry disk to an 11-inch circle. Fit the pastry into a 9-inch pie plate, making sure to press the pastry into the sides and the bottom. Roll out the second disk of pastry and cut strips to make a lattice, if desired, or just roll out as a full top crust. Place the lattice strips or top crust in the refrigerator until ready to use.

Peel the peaches, if desired, then halve and pit them. Dice the peaches into bite-sized pieces and transfer them to a large bowl.

To the bowl, add the sugar, quick-cooking tapioca, orange zest and juice, vanilla extract, nutmeg, and salt. Let the fruit macerate and the tapioca soften for 10 minutes. Add in the blueberries and carefully toss to coat.

Place the filling and all the juices inside the pie shell. Arrange the fruit in the pie crust to eliminate any gaps and lightly press down on the mixture to compact it.

Place the top pie crust over the filling as a lattice (or as a full crust, if desired). Trim the edges and crimp the bottom and top crusts together. (If making a full crust, cut a few slits in the crust to help the steam escape while it is baking.)

Brush the top crust with an egg wash and sprinkle with coarse sugar, if desired.

Bake the pie on a rimmed baking sheet on the lowest rack for 25 minutes.

Lower the oven temperature to 400ºF. If the crust is browning, cover the outer edges with aluminum foil or a pie shield, leaving the middle of the crust exposed. Bake until the juices are bubbling and the temperature of the middle of the pie reaches above 200ºF, another 35 to 40 minutes.

Transfer to a wire rack to cool. Let the pie cool at room temperature for at least 6 hours to let the juices set up.

Serve at room temperature.