Prepare a 9-inch springform pan with parchment paper, and preheat an oven to 180c (350f).
Make the crust: pulse Oreos in a food processor until fine crumbs form. If you don’t have a food processor on hand, place the Oreos in a Ziplock bag and smash them with a cup until fine crumbs form.
Into a small to medium mixing bowl, add the oreo crumbs, and melted butter. Mix with a spoon until the crumbs are coated with butter.
Transfer the crumbs into a prepared 9-inch cake pan, pressing evenly and firmly into the pan.
Bake the crust in a 180c (350f) preheated oven for about 5-8 minutes. Keep an eye on the crust and make sure it doesn’t burn. Take the crust out of the oven and let it cool to room temperature.
Lower the temperature to 140c (280f).
In a big mixing bowl, add the room temperature cream cheese, salt, sugar, and vanilla extract, and mix with an electric hand mixer until the cream cheese is creamy.
Add the sour cream, espresso powder, sift the cocoa powder and mix until combined.
Melt the chocolate and let it cool to room temperature and pour it into the mixture, add the heavy cream as well. Mix until well combined.
Lower the hand mixer speed to low, and add each egg at a time. This step stops the cheesecake batter from overbeating. Overbeating can cause a weird cheesecake texture and stop the cake from cracking.
Pour the cheesecake batter over the crust, and release air bubbles by tapping the pan onto a flat surface.
Bake the cheesecakes in a preheated 140c (280f) oven for about 50 minutes or until the edges of the cheesecakes are set, but the middle is a bit jiggly. Keep the oven door closed for 5 minutes.
Open the oven door halfway, and let the cheesecake cool to room temperature for 1-2 hours. After the cheesecake is cooled, wrap the cheesecake with a plastic wrap tightly, and place the cheesecake in the fridge to cool completely for at least 5 hours.