DEEP DISH BLUEBERRY/PEACH PIE WITH DOUBLE THE CORNMEAL

makes one 8-inch pie, baked in an 8-inch diameter by 2-inch deep fluted quiche pan with removable bottom (Alternatively, bake in a standard 9-inch x 1½-inch deep pie plate) 
A few notes:
Baking this pie early in the day is key to serving it that evening. Baking this pie late in the day means the pie will need an overnight cool down before enjoying, so plan accordingly. It’s best to prepare the crumble topping and the par baked crust the day before.
Oven temperature: Both the crust and the crumble are prone to getting toasty. This pie requires babysitting while it bakes; I start the pie at 375 and then reduce the heat. My oven adjusts downward by degrees; I find the sweet spot in my oven for baking this pie is 365 degrees F. (If your oven only decreases in increments of 25, better to bake lower and longer; start at 375 then bake for the remainder at 350.)
 
For the par baked crust:
1 cup all purpose flour
¼ cup stoneground cornmeal
3 tablespoons confectioner’s sugar
1 teaspoon orange zest
½ teaspoon Diamond Crystal kosher salt (or ¼ teaspoon table salt)
3 oz. (6 tablespoons) cold, unsalted butter, cut into pieces
1 large egg yolk whisked together with 2 tablespoons + 1½ teaspoons ice cold water
In the bowl of a food processor fitted with the blade attachment, place flour, cornmeal, sugar, zest and salt. Pulse a few times to combine. Add cold butter pieces and pulse briefly just until crumbly. Don’t over process. Transfer the mixture to a large bowl and drizzle in the egg yolk/cold water, tossing with a fork to combine. Gather up the pastry; it should hold together but not be wet/sticky. (If it feels too dry, add an additional teaspoon of cold water.) Gather into a disc, flatten slightly and wrap in plastic wrap. Refrigerate for one hour before rolling out.
Butter the inside of the quiche pan making sure you really get inside the nooks and crannies, and dust with flour, shaking out the excess. Retrieve the dough from the fridge and roll it out between two pieces of parchment paper or two pieces of plastic wrap, to prevent it from sticking.  The dough should be about 11 inches in diameter, large enough to accommodate the depth of the pan. Use your rolling pin to maneuver the dough into the pan. Lightly dust the pin with flour, roll up the dough over the pin, then place the pin over the edge of the pan and carefully unroll the pin so the dough drapes inside the pan. Use your fingers to line the pan, making sure you press the dough along the bottom and up and around the sides so it fits snugly. You should have a little excess dough at the top of the pan; create a smooth edge by using your thumb and forefinger to roll the excess towards the top edge of the pan. Refrigerate the dough-lined pan while you prepare the crumble.
 
For the crumble:
⅓ cup sugar
1 teaspoon orange zest
½ teaspoon ground ginger
1¼ cups all-purpose flour
¾ cups stoneground cornmeal
1 teaspoon baking powder
¼ teaspoon kosher salt
½ cup cold, unsalted butter, cut into small pieces
1 large egg, beaten
In a medium bowl, whisk together sugar, zest, ginger, flour, cornmeal, baking powder and salt. Using a bench scraper, cut in the cold butter until the mixture forms coarse crumbs. Gradually add the beaten egg using a fork to incorporate it with the crumbs. Pinch the mixture together to form a crumble, cover with plastic wrap and refrigerate.
Par bake the crust:
Heat the oven to 375 degrees. Retrieve the pie shell from the fridge, line with parchment or foil and dried rice or beans. Place on a baking sheet and bake on the bottom rack of the oven for 15-20 minutes until the crust is lightly golden. Lower the oven heat to 350 degrees. Remove the baking sheet and pie shell from the oven. Carefully remove the parchment/foil and rice/beans and set aside. Check the bottom and sides of the shell for doneness. If it feels slightly raw to the touch, return to the oven for 5 to 8 minutes. Remove pie shell from oven and set aside to cool. Increase the oven temperature back to 375 before you place the assembled pie in the oven.
 
Gather together ingredients for the filling:
1 pound fresh peaches (or nectarines), rinsed, peeled (optional), pitted and sliced thickly
4 cups fresh blueberries, rinsed, picked over for stems, dried on a paper towel
zest of 1 orange
1 teaspoon vanilla extract
½ cup granulated sugar
2-3 tablespoons dark brown sugar, depending on the sweetness of the peaches
3 tablespoons cornstarch
¼ teaspoon ground ginger
⅛ teaspoon salt
In a large bowl, toss together the peaches (or nectarines), berries, zest, and vanilla. In a medium bowl, whisk together the granulated and dark brown sugar, cornstarch, ginger and salt. Just before assembling the pie, toss the fruit with the dry ingredients; stir to coat using a rubber spatula. Taste the fruit- if it needs the additional tablespoon of brown sugar, add it now.

Place the par baked shell on a parchment lined baking sheet.  Spoon the filling into the shell and cover it with the chilled cornmeal crumble. (Don’t compact the filling; just cover the fruit generously.) Bake the pie on the bottom rack of the oven for 20 minutes at 375 degrees F. After 20 minutes, reduce the oven heat to 365 degrees F (see note above) and move the pie to the middle rack of the oven. Bake for an additional 30-40 minutes, rotating the pie from front to back, until the crumble is golden and the fruit is bubbling thickly around the edges. You will need to check on the pie during the bake. If the crumble is getting too toasty, cover the pie with a sheet of aluminum foil. Every oven is different; total bake time on the pie can be upwards of one hour.
Remove the pie to a rack to cool completely. If you attempt to remove the pie from the pan before it has cooled COMPLETELY, you run the risk of damaging the crust. Baking this pie early in the day is key to serving it that evening. Baking this pie late in the day means the pie will need an overnight cool down before serving. Use a small paring knife or offset spatula to loosen any baked-on fruit that has bubbled up against the edge of the quiche pan. Take your time; removing the outer ring of the pan takes patience. For neat slices, chill the pie after removing the outer ring and use a serrated knife. Leftover pie can sit on the kitchen counter, covered with a clean kitchen towel for a day. Beyond that, best to cover and refrigerate.