• Preheat the oven to 350°F. For the crust, you can use either 2 9-inch premade pie crust for the top and bottom crust, or make our homemade pie crust.
• Lightly spray a 9-inch deep dish pie plate with nonstick spray and set it aside.
• If you are using a premade pie crust, center the pie crust in the pie plate.

Frozen Blueberry Filling

• Add the frozen berries to a heavy bottom 4 to 5 quart saucepan.
• Stir in the cornstarch, sugar, lemon zest, lemon juice, and vanilla extract. Stir well to coat the frozen berries.
• Cook the berry mixture on medium to medium-high heat. Stirring well until the berries start to “melt” and the sugar starts to dissolve. Cook for 20 minutes or until the filling becomes thick.
• You need to let the filling cool a bit before pouring into the pie crust and doing the lattice. The hot filling will melt the buttery pie crust.
• Pour the pie filling into the pie crust.

The Lattice Top

• Lightly flour the surface you will be using. Roll out the pie crust with a rolling pin to a 10 to 12 inch circle.
• Using a pizza or a pastry cutter, cut 1 inch wide strips. You will need 10 of the strips, 5 for vertical and horizontal strips.
• Starting at the center of the pie, lay down one of the longest strips and shorter strips closer to the edges.
• Fold the 2nd and 4th strips halfway back. Lay 1 of the longer strips in the center. Unfold the 2 strips.
• Fold back the 1st, 3rd and 5th strips back in the same direction as the 2nd and 4th strips. Lay another strip and unfold strips like the previous strips.
• Fold the 2nd and 4th strips for the final strip of dough on the side. Unfold the 2nd and 4th strips. Turn the pie around and repeat the previous weave of pie strips.
• Once the lattice is woven, trim the overhanging dough about a ½ inch all the way around.
• Roll the edges of the overhang, slightly pinching the dough together as you roll to help seal the lattice and bottom crust.
• Using your index finger and thumb on one hand and the thumb or index finger of the other hand, begin to crimp the edges for a nice finishing touch.
• In a small mixing bowl, whisk together the large egg and cold water until completely combined.
• Brush the egg wash onto the edges and all over the lattice top with a pastry brush.
• Place the pie on a cookie sheet lined with foil for easy cleanup in the case of pie bubble over while baking.
• Bake for 1 hour to 1 hour 15 minutes, or until the top and bottom crust are golden.