Roll out one part of the crust and line a 9 inch pie plate and set aside.
In a large bowl, combine the blueberries, sugar, cornstarch, salt, zest, lemon juice. Toss to coat.
Pour filling into prepared pie plate.
Roll out the second piece of crust and then using a pizza cutter, cut strips of crust to form a lattice style top for the pie.
Place one strip through the middle of the pie and then arrange the other strips in a row from the middle.
Fold the strips in half and begin weaving strips of pie crust in the opposite direction.
Once the strips are arranged in a lattice or basket weave design, cut the longer pieces off and crimp the strips to the bottom crust to keep everything together.
With a basting brush, brush the egg wash onto the crust and top with sanding sugar.
Place pie into the 425 degree oven for 15 minutes. After which lower the temperature to 375 degrees and continue baking for 30 minutes
After 30 minutes, check the pie and make sure the crust isn’t getting too dark. If it is, tenting with aluminum foil will stop the crust from burning.
Once the pie is finished baking, this is the hard part—let it cool for at least 2-3 hours. If it’s cut into too soon it will be too loose. By letting it sit, the cornstarch has time to work its magic!