Make the cherry puree. Pit the cherries and add to a small saucepan with the sugar and place over medium heat. Gently boil them until the cherries are completely soft.
Add the cherries to a blender or use a stick blender to puree the mixture. Once pureed you should have about 1 cup or 250ml of liquid.
Add the pureed cherries back into the saucepan and bring to the boil. Reduce the mixture down to about 150mls so that it's nice and thick. Set aside to cool in the fridge.
Add the chocolate biscuits to the food processor and blitz to a fine crumb. Add in the melted butter and mix until you get the consistency of wet sand. Place the biscuit mixture into a round springform pan that’s been lined with baking paper and press down firmly with the bottom of a glass until it’s evenly covering the base. Set aside in the fridge to chill for about 30 minutes.
Place the cream cheese into the bowl of a stand mixer with the paddle attachment fitted and begin mixing, slowly before turning up to medium. Whip the cream cheese for at least 5 minutes or until it’s looking really creamy. Stop the mixer and add in the vanilla and continue to whip for another 5 minutes scraping down the sides and bottom of the bowl to make sure the mixture is beating evenly.
Once this mixture is combined, with the mixer running on medium low, slowly drizzle in the sweetened condensed milk a little at a time. Continue beating until all of the condensed milk has been added and the mixture is smooth. Add in about a ¼ of a cup of the cherry puree and beat until completely smooth and combined.
Pour half of the filling mixture into the pan and then dollop on a few spoonfuls of the cherry puree. Use your spoon or a skewer to marble the cherry puree through the cheesecake. Repeat with the remaining filling and cherry puree.
Place the cheesecake in the fridge to set for a minimum of 24 hours before slicing and serving. Serve topped with fresh cherries and more chocolate.