In a large bowl, combine the blueberries, sugar, cornstarch, lemon juice, cinnamon, nutmeg, and salt.
6 cups fresh blueberries, ¾ cup granulated sugar, ⅓ cup cornstarch, 1 tablespoon lemon juice, ½ teaspoon ground cinnamon, ⅛ teaspoon ground nutmeg, ⅛ teaspoon kosher salt
Place the pie crust over the pie dish, and gently adhere the crust to the bottom and sides of the dish, being careful to not stretch the dough. Trim away any excess dough so the crust is at an even height with the pie dish.
2 9-inch refrigerated pie crusts
Pour the blueberry filling into the pie dish and top with the butter cubes. Chill while preparing the top crust.
1 tablespoon unsalted butter
Preheat oven to 400°F.
For a lattice crust, place the 2nd crust on a floured surface.
Use a pizza cutter or knife to cut the dough into long strips about 1-inch wide.
Evenly drape 5 strips over the pie, leaving about one inch in between each strip.
Peel back the 2nd and 4th strips, stopping in the middle of the pie.
Place a strip in the middle of the pie in the opposite direction.
Fold back the 2nd and 4th strips. Then, peel back the 1st, 3rd, and 5th strips. Place a second strip in the opposite direction about 1 inch apart from the middle strip. Then, fold back the 1st, 3rd, and 5th strips, and again, peel back the 2nd and 4th strips before place another strip in the opposite direction. Continue this sequence for the remainder of the strips until you have a total of 5 strips placed in the opposite direction. Trim the excess dough spilling over the pan. Carefully tuck the ends of the strips over the filling and into the edges of the crust. Crimp the pie crust edges.
Whisk together the egg and water. Then, brush the egg wash over the pie crust.
1 large egg, 2 tablespoons water
Sprinkle the turbinado sugar over the crust.
Turbinado sugar
Bake for 20 minutes.
Reduce the oven temperature to 350°F and bake for another 20 minutes. Check the pie and cover the outer crust with tin foil if becoming too browned. Bake for another 20-30 minutes until the filling is bubbly.
Let the pie cool completely before serving.