Place the chocolate in a heatproof bowl and melt over a water bath, stirring occasionally.
In the meantime, beat the cream cheese with an electric hand mixer or stand mixer until smooth and creamy. Then mix in sugar, cocoa powder, cornstarch and vanilla until combined. Add the cream and melted chocolate lastly and stir until smooth and creamy. Please make sure to mix just until combined.
Place the prepared wrapped pan in a larger baking pan. Fill in the cheesecake filling. Then pour about 1,5 inch of hot water into the baking pan. Place it in your preheated oven and bake in the water bath for 1 hour.
Turn off the oven and let the cake sit in the oven for further 30-60 minutes with the oven door cracked. Don’t worry if the cheesecake is still wobbly because it will set as it cools.
Then, remove the cake from the water bath and place on a wire rack. Carefully, remove the foil, run the tip of a knife around the sides of the pan. Cool to room temperature, then place in the fridge overnight before removing from the pan.