• Preheat the oven to 350°F and get a 9-inch springform pan ready.

Make the Crust:

• In a food processor, crush the Oreos for 2 minutes or until completely crumbled.
• Add the melted butter and pulse until the mixture looks like wet sand.
• Press the crust into your 9-inch springform pan, making it quite thick on the bottom and about an inch up the sides of the pan.

Bake the Crust:

• Bake the crust for 8 to 10 minutes or until set.
• Allow the crust to cool and then reduce the oven to 325°F for the next bake.

Make the Cheesecake Filling:

• With a hand or stand mixer, beat the cream cheese with the powdered sugar and cocoa powder until combined and smooth, 2 or 3 minutes.
• Mix in the sour cream, and beat on low for a minute or 2 until smooth.
• Keeping the speed low, beat in the eggs until just combined. Don’t overbeat them.
• Use aluminum foil to wrap the bottom of the cooled springform pan well or else use a baking bag to stop any excess water getting into the cheesecake filling.
• Now pour the cheesecake filling into the prepared springform pan and tap the pan a few times on the counter to get rid of any air bubbles.
• Put a lint-free towel in the bottom of a large roasting pan and put the cheesecake on top.
• Pour hot water into the roasting dish outside the springform pan until it reaches about halfway up the pan sides.

Bake the Cheesecake:

• Carefully put the water bath and pan in the oven and bake for 55 to 75 minutes or until the cheesecake edges are set and the middle still has a slight jiggle.
• Turn the oven off, leaving the oven cracked for an hour while the cheesecake and oven cool down.
• Take the cheesecake out of the water bath and let it cool at room temperature for another hour.
• Cover with plastic wrap and refrigerate the chocolate cheesecake overnight.

Make the Ganache:

• Put the dark chocolate chips in a medium, heat-safe bowl.
• Heat the heavy cream in another microwave-safe bowl for 30 seconds at a time, stirring well between heating until it’s steaming, about 2 minutes depending on the wattage of the microwave.
• Next, pour the steaming cream over the dark chocolate chips, without stirring.
• Allow the ganache to set for 5 minutes, then whisk well until the ganache is smooth and thick.

Add the Ganache to the Cheesecake:

• Pour the warm ganache over the cheesecake and then let it cool for 10 to 15 minutes or until it reaches room temperature.
• Once set, garnish with chocolate squares and chocolate shavings, slice and serve.