Blueberry pie doesn't need much introduction. It's widely known to be pretty perfect. Of course America's Test Kitchen made it even more so, with the addition of one apple, the better to keep the filling from running (it's the pectin, you see). Enjoy!
Foolproof Pie Dough
2 1/2 cups (12 1/2 ounces) all-purpose flour
2 tablespoons sugar
1 teaspoon salt
12 tablespoons unsalted butter, cut into 1/4-inch-thick slices and chilled
8 tablespoons vegetable shortening, cut into 4 pieces and chilled
1/4 cup vodka, chilled
1/4 cup cold water
2 tablespoons instant tapioca (or 5 tsp pearl tapioca)
30 ounces (6 cups) blueberries (unthawed frozen work too)
1 Granny Smith apple, peeled and grated on large holes of box grater
2 teaspoons grated zest plus 2 teaspoons juice
3/4 cup (5 1/4 ounces) sugar
2 tablespoons unsalted butter, cut into 1/4-inch pieces
1 large egg, lightly beaten with 1 teaspoon water
FOR THE FOOLPROOF PIE DOUGH: Process 1½ cups flour, sugar, and salt in food processor until combined, about 2 pulses. Add butter and shortening and process until homogeneous dough just starts to collect in uneven clumps, about 15 seconds, scraping down bowl as needed; dough will resemble cottage cheese curds and there should be no uncoated flour. Add remaining 1 cup flour and pulse until mixture is evenly distributed around bowl and mass of dough has been broken up, 4 to 6 pulses. Empty mixture into medium bowl.
Sprinkle vodka and water over mixture. With rubber spatula, use folding motion to mix, pressing down on dough until dough is slightly tacky and sticks together. Divide dough into 2 even balls and flatten each into 4-inch disk. Wrap each in plastic wrap and refrigerate for at least 45 minutes or up to 2 days.
Remove 1 dough disk from refrigerator and roll out on generously floured (up to ¼ cup) counter to 12-inch circle, about ¹/8 inch thick. Roll dough loosely around rolling pin and unroll into 9-inch pie plate, leaving at least 1-inch overhang on each side. Working around circumference, ease dough into plate by gently lifting edge of dough with one hand while pressing into plate bottom with other hand. Leave dough that overhangs plate in place; refrigerate while preparing filling until dough is firm, about 30 minutes.
FOR THE BLUEBERRY FILLING: Adjust oven rack to lowest position, place rimmed baking sheet on oven rack, and heat oven to 400 degrees. Grind tapioca to powder in spice grinder. Place 3 cups berries in medium saucepan over medium heat. Using potato masher, mash berries several times to release juices. Continue to cook, stirring frequently and mashing occasionally, until about half of berries have broken down and mixture is thickened and reduced to 1½ cups, about 8 minutes. Remove from heat and let cool slightly.
Place grated apple in clean kitchen towel and wring dry. Transfer apple to large bowl. Add cooked berries, remaining 3 cups uncooked berries, lemon zest and juice, sugar, tapioca, and salt; toss to combine. Pour filling into dough-lined pie plate and scatter with butter pieces.
Roll out second dough disk on generously floured (up to ¼ cup) counter to 11-inch circle, about ¹/8 inch thick. Using 1¼-inch round biscuit cutter, cut round from center of dough. Cut another 6 rounds from dough, each 1½ inches from edge of center hole and equally spaced around center hole. Roll dough loosely around rolling pin and unroll over pie, leaving at least ½-inch overhang on each side.
Using kitchen shears, trim overhanging dough to ½ inch. Fold dough under itself so that edge of fold is flush with outer rim of pie plate. Flute edges using thumb and forefinger or press with tines of fork to seal. Brush top and edges of pie with egg mixture. If dough is very soft, chill pie in freezer for 10 minutes.
Place pie on heated baking sheet and bake for 30 minutes. Reduce oven temperature to 350 degrees and continue to bake until juices bubble and crust is deep golden brown, 30 to 40 minutes longer. Transfer pie to wire rack; cool to room temperature, at least 4 hours. Cut into wedges and serve.