Preheat the oven to 240℃ / 464℉.
Line a 15cm or 20cm loose bottom or springform cake tin with baking paper and cooking spray. I cut the baking paper into a circle for the base and then I cut a long thick strip to line the circumference of the baking tin. Make sure the baking paper surpasses the edge of the baking tin by half as the cheesecake rises quite a bit.
Add the cream to a medium bowl and heat in the microwave until warm. Add the roughly chopped chocolate and mix until the chocolate has fully melted. Set aside.
In a large bowl, beat the cream cheese until smooth. Whisk the 3 eggs together and add to the cream cheese mixture. Beat until well combined. Add the sugar and beat again until smooth and creamy.
Add instant coffee, cocoa powder and salt. Beat until fully combined.
Pour in the slightly cooled but melted chocolate and until fully combined. Gently pour the Basque mixture in to your prepared baking tin.
Bake on the middle rack for 20-25 minutes. Remove from the oven and allow to rest until it reaches room temperature. The cheesecake will be VERY jiggle and "undercooked" but that how you achieve that mousse like filling. Once cooled, allow the cheesecake to chill in the fridge for 4 hours or overnight. Note: the longer it chills the less "mousse-like" the filling will be.