Place an oven rack on the lowest position in your oven. Preheat oven to 450°F.
Line a 9-inch pie plate with half of the pie dough.
1 pie crust for a 9-inch double-crust pie
In a small bowl, stir together 3 tablespoons of the granulated sugar with 1 tablespoon of the flour until well combined. Sprinkle this mixture over the bottom of the pie crust. Set aside.
⅔ cup granulated sugar, ½ cup all-purpose flour
In a large bowl, gently stir together the remaining granulated sugar, remaining flour, peaches, blueberries, brown sugar, lemon juice, vanilla, and spices until well combined. Add the filling to the pie plate.
⅔ cup granulated sugar, ½ cup all-purpose flour, 4 cups peeled and sliced fresh peaches, 1 ½ cups fresh blueberries, 3 tablespoons lightly packed light brown sugar, 1 tablespoon lemon juice, 1 teaspoon vanilla extract or vanilla bean paste, ½ teaspoon ground ginger, ½ teaspoon cinnamon, Pinch of fine sea salt
Cover the pie with the second half of the pie dough. If you’d like to make a lattice crust, see notes below for directions. Seal and crimp the edges of the pie. If you did not make a lattice crust, use a sharp paring knife to cut slits in the top of the pie to allow steam to escape.
In a small bowl, whisk the egg and milk together until well combined. Lightly brush the egg wash over the crust and sprinkle with the coarse sugar.
1 large egg, 2 teaspoons milk, 1 to 2 teaspoons coarse sugar
Set the pie on a rimmed baking sheet and place on the bottom oven rack. Bake for 15 minutes, then reduce the heat to 350°F and continue baking for another 40-45 minutes, or until the crust is golden and the juices are very bubbly.
Allow the pie to cool before slicing and serving.
Notes
Ingredients
If using frozen peaches and/or blueberries, you do not need to thaw the fruit first. You may need to add a few more minutes of baking time to compensate for the fruit being frozen.
Making a lattice crust
To make a lattice crust, roll out the pie dough until it is large enough to cover the top of the pie. Using a pizza cutter or pastry wheel, cut the dough into strips about 1-inch wide. Lay half of the strips over the top of the pie, leaving about 1 inch of space between each strip. Weave in the remaining dough—this is easiest if you fold back every other piece already on the pie, lay a strip of dough down perpendicular to the rest, then fold the first strips back down. Repeat, this time folding back the strips that you did not fold back the first time. Continue until all of the strips are used and the pie is covered in a lattice pattern.
If I have extra pieces of dough leftover after trimming the edges or weaving the lattice crust, I will sometimes use a very small cookie cutter—such as a heart, star, or flower—to cut shapes out of the pie dough. Use the egg wash to “glue” these to the top of the pie before baking. Lightly brush the tops with the egg wash after adhering them and sprinkle with coarse sugar as desired.
Baking
If the edges of the pie start to brown too much before the pie is done baking, cover the edges with a pie shield or lightly cover with aluminum foil.
Storage
Store covered at room temperature for 1-2 days or in the refrigerator for up to 4 days.
Freezing
Assemble the pie as written in a metal pie plate; do not bake. Place in the freezer for 2-3 hours or until frozen. Wrap in plastic wrap followed by heavy-duty foil. Freeze for up to 3 months. Unwrap and bake from frozen at the directed temperatures, adding an extra 20-30 minutes of baking time at the end.