In a glass bowl add chocolate and melt it in microwave about 30 seconds at a time or use double boiler method.
Add cream cheese into the melted chocolate and mix it well until combined well, keep aside at cool place.
In another big glass bowl add whipping cream and whip it till stiff foamy peaks form, do not over whip otherwise it will become butter.
Add prepared chocolate mixture into the whipped cream and gradually fold the mixture, add vanilla extract while folding the mixture.
Fill the prepared mixture into the piping bag, do not cut the end and keep it into the refrigerator about 4-5hrs or overnight.
Just before serving cut the end and pipe out the mixture into the serving glass, dust the cacao powder over it and dcor with Oreo chocolate cookie or shaved chocolate and serve chilled.