BLUEBERRY SLAB PIE

Steps:

• In a large, flat-bottomed bowl, combine flour, sugar, and salt. Add the butter cubes and toss to coat with the flour mixture. Use a pastry blender to cut the butter into the flour; do not smash or smear the butter. Scrape butter off the pastry blender during the mixing process and continue mixing. (If butter is softening too fast, put the bowl in the refrigerator until butter firms up, 2-5 minutes.) Continue cutting, working quickly, until butter is broken down and looks like a coarse crumble with only a few larger pieces.
• Combine vinegar with water and ice; you'll use up to 1½ cups of this liquid in the pie dough, a tablespoon at a time. Begin by sprinkling about 8 tablespoons of liquid over the flour mixture; use a bench scraper or your hands to incorporate until the mixture begins to come together. Sprinkle in 8 more tablespoons of liquid and continue the mixing process. Squeeze a fistful of dough: if it holds, like wet sand, it's ready. If it falls apart, add 1-2 more tablespoons of liquid at a time, squeezing the dough to check if it holds. Bring all the dough together, sprinkling dry bits with more small drops of liquid as necessary; dough will look shaggy. Knead in the bowl just until incorporated.
• Turn dough onto a work surface and use a bench scraper to divide dough into two equal pieces. Shape into flat disks and wrap in plastic; refrigerate for at least 30 minutes, preferably overnight. Dough can be refrigerated for up to 3 days and frozen up to 1 month, tightly wrapped.
• Generously butter a baking sheet and line with parchment paper. Dust a large work surface and tapered French rolling pin with flour. Roll out 1 disc of chilled pie dough into a rectangle by rolling it in an "X," diagonally, for even stretching. (If dough is softening too fast at any point in the rolling process, chill in the refrigerator until firm, 2-5 minutes.) Once the dough has been thinned out, switch to a straight French rolling pin and continue rolling the dough until it's a rectangle of even thickness, 3-4 inches larger than the baking sheet. Fit the dough into the baking sheet by gently folding in half, then in half again. Align the creases squarely in the middle of the pan, then unfold the dough so it's centered in the pan. There should be a 1-inch dough overhang on all sides. (If necessary, it's okay to stretch the dough gently.) Repeat the rolling and shaping process with top crust dough to a 17" x 13" rectangle. Invert a rimmed baking sheet and spread the dough on top. Refrigerate both sheets while assembling the filling, 20 minutes.
• Filling: Taste your blueberries first. They can vary from really sweet to really tart which will affect how much sugar is added; add or take out up to ¼ cup sugar to adjust sweetness. In a small bowl, mix shredded apple with lemon juice. In a large bowl, combine both sugars, Angostura bitters, allspice, cloves, cinnamon, cardamom, salt, and ground arrowroot. Add the blueberries, crushing about half of them with your hands; mix well to combine, making sure no spices remain at the bottom of the bowl.
• Preheat oven to 425 F. Remove the chilled dough sheets; set the top dough aside. Transfer the filling into the dough-lined baking sheet, patting it down to make sure there are no gaps. Use the round pastry cutter to punch random holes into the top dough, 2-3 inches apart, to create a polka dot effect; don't get too close to the edges. (Save the pastry circles to make crust cookies!) Place the top dough sheet squarely over the filling, then seal the top and bottom crusts by tucking and pinching excess dough under the bottom crust. Seal again by pressing circumference of crust with your thumbs.
• Brush egg wash evenly over the top crust, and sprinkle with raw sugar. Pie will bake for a total of 1 hour. Bake on the lowest rack of the oven until crust is set and beginning to brown, 20-25 minutes. Lower heat to 375 F, move the pie to the center oven rack, and continue to bake until crust is a deep golden brown and juices are bubbling throughout, about 30-35 minutes longer. Allow pie to cool completely on a wire rack before cutting into it, 1-2 hours. Serve slightly warm or at room temperature.