Preheat your oven to 325°F (160°C) and lightly grease a 9-inch springform pan.

In a mixing bowl, combine 2 ½ cups of Oreo cookie crumbs with ½ cup of melted unsalted butter, then press the mixture into the bottom of the prepared pan.

Chill the crust in the refrigerator for 10 minutes while preparing the filling.

In a large bowl, beat 4 packages (8 oz each) of softened cream cheese and 1 cup of granulated sugar together until smooth.

Add in ½ cup of sour cream, 4 large eggs, 1 tablespoon of vanilla extract, and 2 tablespoons of cocoa powder, then mix until fully combined.

Fold in 1 cup of crushed Oreo cookies gently with a spatula.

Pour the cheesecake filling over the chilled crust and smooth the top.

Bake for 60 to 75 minutes until the edges are set and the center has a slight wobble when shaken.

Turn off the oven and leave the cheesecake inside for about 1 hour to cool gradually.

Wrap the springform pan in plastic wrap and refrigerate for a minimum of 6 hours or overnight.

Before serving, top with cream cheese frosting or chocolate ganache and sprinkle additional Oreo crumbs on top.