Crust:

3 cups all-purpose flour (we did 1/2 whole wheat pastry flour and 1/2 white flour)
1 tablespoon sugar or succanat
1 1/2 teaspoons salt
20 tablespoons (2 1/2 sticks) cold unsalted butter, cut into small pieces
4 to 5 tablespoons ice-cold water

Filling:

3 pounds ripe peaches (approximately)
2 tablespoons fresh lemon juice
1 cup blueberries
1 tablespoon vanilla extract
1/3 cup (packed) light-brown sugar OR succanat
1/4 cup granulated sugar OR succanat OR honey
1 packet Stevia
1/4 cup all-purpose flour OR whole wheat pastry flour
1 large egg white, lightly beaten
2 tablespoons cold unsalted butter, cut into small pieces
2 tablespoons heavy cream

Prepare the crust:

Put the flour, sugar and salt in the food processor; pulse until just combined
Add the butter and shortening; pulse until the texture of coarse meal
Gradually add the ice water, pulsing until the dough holds together
Divide the dough in half and form into 2 balls
Wrap in plastic and chill in the refrigerator for at least one hour, or overnight

Butter a 9-inch Pyrex pie dish
Remove one dough ball from the refrigerator
Roll it out on a lightly floured surface to form a round, 1/8-inch thick and 2 inches larger than the pie dish
Gently transfer it to the center of the pie dish
If the dough should tear, just press it lightly together
Trim the dough, leaving a 1-inch overhang. Place in the refrigerator to keep cold

Line a baking sheet with waxed paper
Remove the other disk of dough from the refrigerator and roll it out the same way
Transfer to the baking sheet and cover with another sheet of waxed paper
Place in the refrigerator to keep cold
Position a rack in the center of the oven and preheat the oven to 425°F

Prepare the filling:

Using a paring knife, cut an “X” in the bottom of each peach
Drop the peaches into a pot of boiling water for 1 minute
Remove to a bowl to cool
When they are cool enough to handle, slip off the skins
Cut the peaches into 3/4-inch slices and place in a large bowl
Toss with the lemon juice to prevent discoloring
Add the blueberries, vanilla, brown sugar, 1/2 cup granulated sugar and the flour; toss well

Assemble pie:

Take the pie crust out of the fridge, lightly brush the bottom with egg white
Spoon in the filling and dot with the butter
Cut the top crust into strips 3/4-inch wide and make a lattice cover over the filling
Trim the overhang to 1 inch
Moisten the edges of the crusts where they meet with a little water, then press them together lightly and turn them under.
Crimp the edges decoratively
Brush the lattice crust and the rim with the cream.
Sprinkle the surface with the remaining 2 tablespoons of sugar

Place the pie on a baking sheet and bake in the oven for 15 minutes
Reduce the heat to 375°F and bake until it is golden and the juices are bubbling, about 50 to 60 minutes
If the top is getting too brown, tent the pie with foil after about 30 minutes
Let the pie cool on a wire rack before serving