Preheat oven to 425 degrees
Line a 9 inch pie plate with one pie crust and trim edges (either store bought or homemade crust), poke holes all around in the bottom with a fork and set aside.
Place the blueberries, sugar, cornstarch, salt, zest, lemon juice in a large bowl and stir gently to combine well.
Pour the blueberry filling onto the pie crust in the pie plate.
Roll out the second crust onto a floured surface. Using a pastry cutter or pizza cutter, cut 1 inch wide strips of crust to form a to use to make a basket weave/lattice top crust.
Place strips across the pie in one direction leaving space between each strip.
Starting at the middle of the pie, begin weaving the other remaining strips of crust in the opposite direction over and under each strip that was lace first. (forming a lattice or basket weave design)
Cut off any remaining long strips at the edges and crimp the strips to the bottom crust to form a seal.
Beat the egg in a small bowl and brush the egg onto the entire crust with a with a basting brush.
Top with turbinado or sanding sugar.
Bake for 15 minutes at 425 degrees F.
Then lower the temperature to 375 degrees F and continue baking for 30 more minutes.
Check to make sure the crust isn’t getting too dark while it's baking. If it is getting too dark then place a piece of aluminum foil gently over top forming a slight tent to prevent burning.
Let the pie cool for at least 2-3 hours. If the pie is cut too soon, the filling will be too runny and loose.