Preheat the oven 350 degrees F, mist an 8-inch diameter by 3-inch deep cake pan with non-stick spray, and line the bottom with a circle cut from parchment paper.
Place the sugar, cocoa, and salt in a large mixing bowl, whisk to combine.
Add the cream cheese, and mix on medium-low speed until combined.
Add the eggs and yolks, one at a time, stopping to scrape the bottom and sides of the bowl with a silicone spatula after each addition.
Stir in the cream, melted chocolate, and vanilla, and transfer the cheesecake batter to the prepared pan.
Place the unbaked cheesecake in a larger pan, and pour very hot water into the larger pan until it comes an inch or two up the sides of the cheesecake pan.
Bake for 20 minutes at 350 degrees F, then lower the oven temperature to 250 degrees F, and bake for another 60 minutes, or until set around the edges but still slightly jiggly towards the center.
Turn off the oven, and prop the door open with a wooden spoon. Allow the cheesecake to cool slowly in the oven for at least an hour.
Refrigerate for 2 hours to overnight before unmolding. (Wrap in a hot towel, if needed, to help release the cheesecake from the pan.)