Make the dough:
Put the flour, sugar, and salt in a food processor and pulse briefly to combine. Add the butter and shortening and pulse until the pieces are slightly larger than pea-size, 10 to 12 pulses. Drizzle the water and lemon juice evenly over the flour mixture. Pulse until the dough forms moist crumbs that just begin to clump together, 8 or 9 more pulses.
Dump the moist crumbs onto two large overlapping pieces of plastic wrap and gather into a pile. With the heel of your hand, push and gently smear the dough away from you, rotating the plastic so you smear a different section each time, until the crumbs come together; 2 or 3 smears should do it. Divide the dough in half (about 12 oz. for each piece); shape one piece into a 5-inch disk and the other into a 4x6-inch rectangle. Wrap each tightly in plastic and refrigerate until firm, at least 2 hours and up to 2 days (or freeze for up to 1 month).
Make the lattice top crust:
Position a rack in the center of the oven and set a foil-lined heavy-duty rimmed baking sheet on the rack. Heat the oven to 425°F.
Remove the rectangle of dough from the refrigerator; if it’s very firm, let it sit at room temperature until it’s pliable enough to roll, 10 to 20 minutes. (If the disk of dough is also very firm, let it sit at room temperature while you make the lattice.)
On lightly floured parchment, roll the dough with a floured rolling pin into a 9-1/2 x14-1/2-inch rectangle that’s 1/8 inch thick. Roll from the center of the dough to the edges and try to use as few passes as possible to avoid overworking the dough. After every few passes, run an offset spatula or bench knife under the dough to be sure it isn’t sticking, and give the dough a quarter turn. Reflour the parchment and the rolling pin only as needed—excess flour can make the crust tough.
Using a fluted pastry wheel or a chef’s knife, trim the dough into a 9x14-inch rectangle. With the wheel or knife, cut 12 strips of dough that are 14-inches long and 3/4-inch wide. If at any point while making the lattice the dough becomes too soft to work with, slide the parchment onto a cookie sheet and chill the dough until firm.
Line a cookie sheet with parchment. Arrange 6 of the dough strips horizontally 3/4-inch apart; these will be the “bottom” strips.
Fold back every other bottom strip to the left slightly more than halfway. Slightly left of center, lay down one “top” strip vertically over the bottom strips, dabbing the bottom strips with a wet finger where the top strip will overlap them. Dab the top strip where the folded strips will overlap it, then unfold the strips. Fold back the other 3 bottom strips to the left. Lay a second top strip 3/4-inch to the right of the first, dabbing with water as before. These are the two center strips. Unfold the bottom strips. Repeat the process on both sides with the remaining top strips of dough.
Press gently where the strips overlap to seal. Loosely cover the lattice with plastic wrap and refrigerate on the cookie sheet while you roll out the bottom crust and make the filling.
Roll and shape the bottom crust:
On lightly floured parchment, roll the disk of dough into a 14-1/2-inch circle that’s 1/8 inch thick.
Carefully and gently roll the dough around the rolling pin and position the pin over a 9-inch glass pie plate. Unroll, easing the dough into the pan. Gently press the dough against the side and bottom of the pan, being careful not to stretch or tear it, and allowing the excess dough to hang over the edges. Let sit at room temperature while assembling the filling.
Make the filling:
In a large bowl, combine the sugar, flour, lemon zest and juice, and salt. Add 1 cup of the blueberries and crush them into the dry ingredients with a potato masher or fork to make a paste. Add the rest of the berries and toss to coat. Scrape the filling into the crust with a rubber spatula, spreading evenly.
Assemble and bake the pie:
Remove the lattice from the refrigerator. If it’s stiff, let it sit at room temperature for a few minutes. Put your palm under the parchment at the center of the lattice. Lift the paper and invert the lattice onto the filling in a swift, smooth motion. Press the top and bottom edges together and trim both crusts so there’s about a 3/4-inch overhang. Roll the overhang under itself to form a high edge of crust that rests on the rim of the pie plate. Using your fingers, crimp the dough into a fluted edge.
In a small bowl, beat the egg and 1 Tbs. water until blended. Using a small pastry brush, brush the egg mixture evenly over the lattice and edge, and then sprinkle generously with the coarse sugar.
Put the pie on the heated baking sheet and reduce the oven temperature to 375°F. Bake until the edges are pale golden, about 30 minutes, then cover the edges with foil and continue to bake until the lattice is golden-brown and the filling is bubbling about 2-inches from the center, 80 to 90 minutes total. (If the lattice is golden-brown before the filling is bubbling, cover it loosely with foil.)
Let the pie cool on a rack to room temperature, about 3 hours, before serving. It’s best eaten on the day it’s made, but you can make it up to 1 day ahead and store it, covered when cool, at room temperature. Leftovers keep in the refrigerator for up to 5 days.
nutrition information (per serving):
Photo: Scott Phillips