Add the cookie crumbs, melted butter and vanilla extract and mix until well combined. Press into bottom of a 9-inch springform pan and set aside.
For the filling:
Mix the milk, sugar, cocoa powder, cornstarch, egg yolks, sour cream, vanilla & salt in a food processor (or mixer) until thoroughly blended and the mixture is smooth with no lumps.
Add the mixture to a large saucepan and bring to a simmer whisking the whole time. Once the mixture comes to a simmer, add the cream cheese, butter, and chocolate chips and whisk until smooth.
Bring the mixture to a boil and whisk for three minutes until the mixture becomes thick and creamy. Pour the mixture into the pan with the crust.
Cover with plastic wrap (make sure the plastic wrap is touching the surface to avoid a skin forming).
Chill cake for at least 4 hours before slicing. To garnish sprinkle with chocolate shavings or curls