Roll one dough on a lightly floured work surface. If dough is too hard or too cold, let it rest a few minutes until it is pliable. Roll dough to about 10-inches in diameter and about 1/4-inch in thickness. Place pie plate upside down over the rolled dough to make sure it is the correct size.
Generously butter the pie plate. Move dough into the prepared pie plate and firmly press it into the bottom and sides of pie plate. Trim excess dough. Cover with plastic wrap and let chill in the fridge.
Roll out the dough dough to 10-inches in diameter. Slice into strips. Punch out leaf shapes using cutters. Cover with plastic wrap and let chill in the fridge for 5 minutes.
Meanwhile, toss blueberries with sugar, grated ginger, salt, and cornstarch.
Pour blueberries in the chilled pie crust. Arrange chilled dough strips over the blueberry filling. Press the ends of the strips into the edges of pie crust. Arrange chilled leaf shapes as desired. Cover pie with plastic wrap and allow to chill in the fridge while oven preheats.
Preheat oven to 375° F.
Egg Wash: whisk together egg, salt, and water until smooth.
Brush pie with egg wash. Sprinkle turbinado sugar, if desired.
Place an aluminum foil tent over pie. Bake for 30 minutes. Remove foil and bake for another 25-30 minutes until pie is golden brown and berry filling is bubbling. Cool to room temperature before slicing.