Preheat your oven to 425F.
Toss the blackberry filling ingredients together until the berries are evenly coated and with your wooden spoon, gently crush the berries just a bit.
Spoon the filling into your crust, leaving the liquid behind in your mixing bowl.
Cover with additional slitted pie crust, and fork the edges.
Brush the egg mixture topping on the top crust and then sprinkle the top with sugar.
As always with pies, cover the edges with foil to prevent the lip of the crust from burning, and remove the foil for the last 15 minutes of baking.
Bake 35-45 minutes or until crust is golden brown and pie is bubbling through the top crust.
Allow the pie to cool before slicing it.