Here’s a pie that has a firm, juicy filling full of fresh blueberry flavor with still plump berries, and also a crisp, flaky crust.
Start to finish: 3 hours
30 ounces (6 cups) blueberries
1 Granny Smith apple, peeled, cored, and shredded
5 1/4 ounces (3/4 cup) sugar
2 tablespoons tapioca starch
2 teaspoons grated lemon zest plus 2 teaspoons juice
1 recipe Double-Crust Pie Dough (recipe below)
1 large egg white, lightly beaten
Cook 3 cups blueberries in medium saucepan over medium heat, mashing occasionally with potato masher to help release juices, until half of berries have broken down and mixture is thickened and measures 1 1/2 cups, about 8 minutes. Let cool slightly.
Place shredded apple in clean kitchen towel and wring dry. Combine apple, cooked berry mixture, remaining 3 cups uncooked berries, sugar, tapioca starch, lemon zest and juice, and salt in large bowl.
Adjust oven rack to lowest position, place foil-lined rimmed baking sheet on rack, and heat oven to 425 degrees. Roll 1 disk of dough into 12-inch circle between 2 large sheets of plastic wrap. Remove top plastic, gently invert dough over 9-inch metal pie plate, and ease dough into plate; remove remaining plastic. Roll other disk of dough into 12-inch circle between 2 large sheets of plastic. Remove top plastic. Using 1 1/4-inch round cookie cutter, cut hole in center of dough, then cut out 6 more holes, about 1 1/2 inches from hole in center, evenly spaced around center hole.
Spread blueberry mixture evenly into dough-lined pie plate. Gently invert top crust over filling and remove remaining plastic. Trim dough 1/2 inch beyond lip of pie plate, pinch dough edges together, and tuck under itself to be flush with edge of pie plate. Crimp dough evenly around edge using your fingers. Brush pie with egg white.
Place pie on preheated baking sheet and bake until crust is light golden brown, about 25 minutes. Reduce oven temperature to 350 degrees, rotate baking sheet, and continue to bake until juices are bubbling and crust is deep golden brown, 30 to 40 minutes longer. Let pie cool on wire rack to room temperature, about 4 hours. Serve.
Makes enough for one 9-inch pie
6 tablespoons ice water
3 tablespoons sour cream
1 tablespoon rice vinegar
13 ounces (2 3/4 cups plus 2 tablespoons) flour
1 tablespoon sugar
1 teaspoon salt
1/2 teaspoon xanthan gum
16 tablespoons unsalted butter, cut into 1/4-inch pieces and frozen for 10 to 15 minutes
Combine ice water, sour cream, and vinegar together in bowl. Process flour, sugar, salt, and xanthan gum together in food processor until combined, about 5 seconds. Scatter butter over top and pulse until crumbs look uniform and distinct pieces of butter are no longer visible, 20 to 30 pulses.
Pour half of sour cream mixture over flour mixture and pulse to incorporate, about three pulses. Add remaining sour cream mixture and pulse until dough comes together in large pieces around blade, about 20 pulses.
Divide dough into two even pieces. Turn each piece of dough onto sheet of plastic wrap and flatten each into 5-inch disk. Wrap each piece tightly in plastic and refrigerate for 1 hour. Before rolling out dough, let it sit on counter to soften slightly, about 30 minutes. (Dough can be wrapped tightly in plastic and refrigerated for up to 2 days.)