• Preheat oven to 375. Lightly spray an 8 inch ceramic or glass pie dish with cooking spray and coat lightly with flour. Set aside.

Crust

• 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 10 minutes.
• Reduce oven temperature to 325.

Filling

• Cream together butter and sugar. Mix in eggs, vanilla, and cocoa. Add melted chocolate and half and half (or light cream) and mix to 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. Simply fill til just below the edge of the crust and discard any extra batter. 
• 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 cool whip evenly over pie. If you desire a "spiky" effect, simply press the back of a spoon into the cool whip, and lift it up again. If desired, drip red food coloring over topping for a "bloody" effect. Cover and chill until ready to serve.