Lightly grease a muffin pan (12) with cooking spray and set aside.
Crush the cookies by hand or in a food processor until you get fine crumbs. Add the melted butter to the crumbs and mix together. Divide evenly the mixture into the muffin pan and press them down tightly. Place in the fridge.
In a large bowl cream together the cream cheese, vanilla, icing sugar and the crushed cookies. Set aside.
Whip the heavy cream and fold it gently in the cream cheese mixture.
Evenly distribute the mixture between all the cavities of the muffin pan. Place in the freezer for about 10 minutes.
While the cheesecakes are setting, melt the chocolate. Top each mini cheesecake with equal amounts of chocolate and top it with half an Oreo. Place in the fridge for 30 minutes.
Before serving the cheesecakes. Take them out of the mold and let rest for about 30 minutes. Enjoy!