Preheat your oven to 325°F (163°C). In a food processor, crush the Oreo cookies until fine crumbs. Combine these crumbs with melted unsalted butter and mix until incorporated. Press into the bottom of a greased 9-inch springform pan. Bake for 10 minutes, then cool.

In a large mixing bowl, beat the cream cheese with an electric mixer until smooth. Gradually add granulated sugar, sour cream, and vanilla extract. Mix until combined. Fold in chopped Oreo pieces.

Pour the filling over the cooled crust. Smooth the top with a spatula. Bake for 60-70 minutes until edges are set and the center jiggles slightly.

Turn off the oven, crack the door, and let cool for 1 hour. Transfer to the refrigerator and chill for at least 4 hours, preferably overnight.

Unlock and remove the springform pan sides. Slice your Oreo cheesecake and serve topped with whipped cream or cocoa powder.