Preheat your oven to 325°F (160°C).
In a bowl, mix the chocolate cookie crumbs and melted butter until combined.
Press the mixture firmly into the bottom of a springform pan to form the crust.
In a large mixing bowl, beat the cream cheese until smooth.
Add the sugar and vanilla extract, mixing until well combined.
Incorporate the eggs one at a time, beating well after each addition.
Mix in the melted chocolate and cocoa powder until fully blended.
Fold in the sour cream until smooth and creamy.
Pour the cheesecake batter over the crust in the springform pan.
Bake for 60 minutes or until the center is set but slightly jiggly.
Turn off the oven and let the cheesecake cool inside for 1 hour.
Chill in the refrigerator for at least 4 hours before serving.