Preheat oven to 325°F (162°C) and line cupcake pan.
Mix Oreo crumbs + melted butter, press into liners, and bake 5 minutes.
Lower oven to 300°F (148°C).
Beat cream cheese, sugar, and cocoa until smooth.
Add sour cream and vanilla, mix gently.
Add eggs one at a time, then mix in melted chocolate.
Fill cups and bake 15 minutes. Turn off oven and let sit 10 minutes.
Cool gradually, then chill in fridge.
Make ganache and spoon over cheesecakes.
Whip cream ingredients until stiff peaks form.
Pipe whipped cream and decorate with chocolate bars.