Preheat oven to 375F.
Lightly spray a glass pie dish with cooking spray and coat lightly with flour and set aside. You can also use small tinfoil pie plates for easy party sharing.
In a large bowl whisk together flour and cocoa powder. Cut in butter with two forks, a pastry knife, or fingertips until mixture resembles fine crumbs.
Add sugar and mix.
Stir in water one tablespoon at a time until mixture begins to come together. Cover with plastic wrap and chill 15 minutes.
Place crust dough in prepared pie dish and lay a sheet of plastic wrap over the entire dish. Press dough into dish until it is shaped to the dish. Be sure to press dough up over the edges of the dish.
Remove the plastic wrap and use a sharp knife to trim away excess dough hanging past the edge of the dish.
Bake for 10 minutes.
Reduce oven temperature to 325.
Prepare the filling by creaming together butter and sugar.
Mix in eggs, vanilla, and cocoa.
Melt the chocolate chips in a bowl in the microwave by 30 second intervals at a time, stirring in between.
Add melted chocolate and cream to egg/butter/sugar/vanilla mixture and combine.
Pour mixture on top of pie crust.
*Depending on how thinly you spread your crust, you may or may not need to use the entire batch of filling. Fill to just below the pie crust and if you have extra, you can place into a ramekin for a gluten free option.
Bake 45 minutes.
Remove from oven and chill one hour or overnight.
**The pie will be tall when you first pull it out of the oven. It will sink as it cools. Once pie has chilled, spread the whipped cream evenly over pie. If you desire a "spiky" effect, press the back of a spoon into the cool whip, and lift it up again.
For the blood, in a sauce pan combine cherry juice, cornstarch and sugars together by whisking over a medium heat until the sauce has thickened. Once cooled, drizzle over top of pies and presentation dish.