Step 1

In a large bowl, mix together the flour, sugar, and salt. Add in the cubed butter and toss with a spatula to coat the butter in the flour.

Step 2

Using a pastry cutter, work the butter into the flour until the mixture is a coarse meal. The butter should be about the size of peas.

Step 3

Using a silicone spatula, slowly blend in just enough ice water to form moist clumps.

Step 4

Pour the shaggy dough out onto a clean surface and knead it gently, until it comes together in a ball, adding more ice water only if absolutely needed.

Step 5

Gather the dough into a large ball and divide it in half (you can use a kitchen scale if you want each side to weigh the same, each half should weigh about 644 grams, depending on how much water is used). Gently flatten each half into a disk.

Step 6

Wrap the disks in plastic wrap and place in the refrigerator to chill for at least 2 hour, or up to 24 hours.

Step 7

In a medium saucepan, combine the 1 pound (397 g) of the blueberries, light brown sugar, lemon juice, and 1 Tablespoon (11 grams) of the cornstarch. Place the pan over medium-high heat and bring to a simmer, stirring almost constantly, and cook just until the mixture starts to thicken, about 7 to 8 minutes.

Step 8

Reduce heat to low and cook for another 2 minutes before removing from heat.

Step 9

Transfer to a large heatproof bowl and stir in the remaining blueberries (397 g), granulated sugar, cinnamon, salt, allspice, vanilla, butter, and remaining cornstarch. Mix well to evenly combine, then set aside to cool completely before using.

Step 10

Remove one disk of the dough from the fridge 15 minutes before you plan on rolling, as dough that is too cold will crack.

Step 11

Lightly flour a rolling pin and a large clean work surface. Set the dough in the middle of the work surface and - beginning from the center of the disc - roll the dough away from you in one firm and even stroke. After each stroke, rotate the disc a quarter turn clockwise and roll again. Lightly sprinkle more flour on the work surface, pie dough, and rolling pin as needed. You want to use just enough to prevent the dough from sticking. As your disc of dough becomes larger, be sure not to overstretch the center of the dough. Continue rolling until the dough is about 16-inches in diameter, and around a 1/4" in thickness.

Step 12

Carefully fold the dough in half and lay it across one side of a 9-inch pie pan, placing the seam of the dough in the center of the pan.

Step 13

Gently unfold the crust, then use your hands to fit the dough down into the pan, making sure there are no gaps between the dough and the sides of the pan. If you see any visible air bubbles, gently burst them with a fork.

Step 14

Using kitchen scissors, trim the dough overhang to 1 and 1/2 inches, measuring from the inner rim of the pan.

Step 15

Lightly cover the crust with plastic wrap and place back in the refrigerator until needed, at least 20 minutes.

Step 16

Remove the second disk of the dough from the fridge and let it sit at room temperature for 15 minutes before you plan on rolling. Remember, dough that’s too cold will crack.

Step 17

Line a large baking sheet with parchment paper and set it aside until needed.

Step 18

Lightly flour a rolling pin and a large clean work surface. Set the dough in the middle of the work surface and - beginning from the center of the disc - roll the dough away from you in one firm and even stroke. After each stroke, rotate the disc a quarter turn clockwise and roll again. Lightly sprinkle more flour on the work surface, pie dough, and rolling pin as needed. You want to use just enough to prevent the dough from sticking. As your disc of dough becomes larger, be sure not to overstretch the center of the dough. Continue rolling until the dough is about 16-inches in diameter, and around a 1/4" in thickness.

Step 19

Using a pizza cutter or pastry roller, slice the dough into 12 strips (the width of the strips should be just over an inch). Gently lay the strips on the prepared baking sheet, cover with plastic wrap, and refrigerate until needed, at least 20 minutes.

Step 20

In a small bowl combine the egg and water, whisk until well combined.

Step 21

Preheat the oven to 425 degrees (F).

Step 22

Remove the prepared crust and lattice strips from the refrigerator.

Step 23

Sprinkle the bottom of the pie crust with 1 teaspoon of flour. Then, using a rubber spatula, scrape the blueberry pie filling into an even layer in the pie crust shell.

Step 24

Lay 7 of the strips parallel on top of the filling, leaving about 1/4-inch between each strip. Fold back the second, fourth, and sixth strip, then place a strip of dough so that it’s perpendicular to the parallel strips. Unfold the folded strips, so they lay over the perpendicular strip.

Step 25

Now fold back the first, third, fifth, and seventh strip, then place another strip of dough on top, so that it’s perpendicular to the parallel lattice strips.

Step 26

Repeat this layering process with remaining lattice strips, weaving the strips over and under each other.

Step 27

Trim the edges of the strips, leaving about 1/2 inch overhang. Tightly roll the excess dough up so it's firmly sitting on the edge of the pie plate, then crimp the edges to secure the strips with the bottom pie crust.

Step 28

Gently brush the edges of the crust and the lattice strips with the egg wash, then sprinkle generously with sparkling sugar.

Step 29

Place the pie on a baking sheet and bake in the lower third of the oven for 15 minutes.

Step 30

Then reduce the oven temperature to 350 degrees (F) and continue baking for 55 more minutes, until the top crust is golden brown and the filling is bubbling.

Step 31

Place the pie plate on a wire rack and cool for 4 hours before slicing.

Step 32

Once the pie is completely cool, it may be wrapped tightly in saran wrap and stored at room temperature for up to 24 hours.