Follow these simple steps to create your delicious Chocolate Cheesecake:

1. Preheat the Oven: Preheat your oven to 325°F (160°C). Grease a 9-inch springform pan.
2. Make the Crust: In a medium bowl, combine graham cracker crumbs, cocoa powder, sugar, and melted butter. Mix until well combined. Press the mixture evenly into the bottom of the prepared pan.
3. Prepare the Filling: In a large mixing bowl, beat the softened cream cheese until smooth and creamy.
4. Add Sugar and Vanilla: Gradually add 1 cup of sugar and the vanilla extract, mixing until well integrated.
5. Include Eggs: Add the eggs one at a time, mixing on low speed until just combined after each addition.
6. Incorporate Chocolate: Pour in the melted semi-sweet chocolate, mixing until fully incorporated and the batter is smooth.
7. Add Sour Cream and Heavy Cream: Fold in the sour cream and heavy cream until the mixture is creamy and uniform.
8. Pour Filling into Crust: Pour the cheesecake filling over the prepared crust, smoothing the top with a spatula.
9. Bake: Place the cheesecake in the preheated oven and bake for 60 minutes, or until the edges are set, but the center is slightly jiggly.
10. Cool Down: Turn off the oven and leave the cheesecake inside with the door slightly ajar for about 1 hour. This helps prevent cracking.
11. Chill: Remove the cheesecake from the oven and let it cool at room temperature. Then, refrigerate for at least 4 hours or overnight.
12. Serve: Once chilled, carefully remove the sides of the springform pan. Top with chocolate shavings or whipped cream if desired.

These steps will guide you through creating an incredible chocolate cheesecake that everyone will adore!