1 cup (2 sticks) unsalted butter, chilled and cut into cubes
4–6 tablespoons ice cold water
2–1/2 pounds blueberries
1/2 cup sugar
1 tablespoon lime juice
1 teaspoon lime zest
3 tablespoons cornstarch
1 large egg, lightly beaten
For the dough, combine the flour, sugar and salt in a large bowl. Use a fork or pastry blender to cut the butter into the flour mixture until it forms pea-sized clumps. Use a spatula or wooden spoon to gradually fold the water into the dry ingredients. When the dough starts to form, use your hands to bring it together into a ball. Divide the dough in half, press into disks and cover with plastic wrap. Chill in the refrigerator for at least 1 hour or up to 2-3 days.
For the filling, stir together the blueberries, sugar, lime juice, lime zest and cornstarch in a large bowl.
Preheat the oven to 375 degrees F.
On a lightly floured work surface, roll out one of the dough disks into an 11-inch diameter circle about 1/8-inch-thick. Transfer the dough to a 9-inch pie plate.
Roll out the remaining dough into a rough 9-inch-by-12-inch rectangle. Cut into strips. Lay half the strips over the pie. Weave the remaining strips in the opposite direction, folding back the perpendicular strips as you go. (For lattice inspiration, try here and here). Trim the strips creating a 1-inch overhang, Tuck the strips under the crust and crimp the edges. Brush with the beaten egg.
Bake the pie for 1 hour to 1 hour & 15 minutes until the crust is golden brown and the filling is bubbling. If the crust starts browning too quickly, loosely cover with foil.