In a large bowl, beat together cream cheese, sugar, and cornstarch until smooth.
Add melted chocolate, sour cream, and vanilla, and mix until combined.
Beat in the eggs, one at a time, until smooth.
Pour the cheesecake batter over the cooled crust and bake for 39-42 minutes, until the center is slightly jiggly.
Let the cheesecake cool completely, then chill it in the fridge for at least 6 hours or overnight.