Begin by pulsing Oreo cookies in a food processor until they resemble fine crumbs. Transfer into a mixing bowl and combine with melted butter. Press into the bottom of a mini cheesecake pan.

Melt the chocolate chips in a microwave-safe bowl, stirring every 30 seconds until smooth. Let cool slightly.

In a large mixing bowl, beat cream cheese, sugar, and cocoa powder until smooth. Add sour cream and vanilla, mixing well.

In another bowl, whip heavy cream and powdered sugar until stiff peaks form, then fold into the chocolate mixture.

Gently fold the melted chocolate into the cream cheese mixture until combined.

Fill each crust with the cheesecake filling using a piping bag and smooth the tops.

Chill the cheesecakes in the refrigerator for at least 4 hours or overnight to set.

Whip extra heavy cream with cocoa powder and powdered sugar until stiff peaks form, then top the cheesecakes.

Run a knife around the edges to loosen, gently lift out, and serve cold.