Line the base of a 22cm springform tin with baking paper and lightly grease the sides. Set aside until needed.
Finely chop two of the Mars Bars and set aside until needed.
Process the chocolate ripple biscuits (or similar) until the resemble breadcrumbs. Add the melted butter and stir until combined.
Pour the biscuit mixture into your prepared tin and use a large metal spoon to cover the base with the mixture and flatten the surface.
In the bowl of an electric mixer, add the softened cream cheese, cream, caster sugar and vanilla extract and mix on a medium to high speed or until the mixture is thick, creamy and smooth.
Meanwhile, chop four Mars Bars into small pieces and place in a microwave safe bowl. Cook for 30 second spurts (stirring in between each cook) until they have melted.
Add the melted Mars Bars to your cream cheese mixture and mix on a medium speed to combine. Remove the mixer bowl from the stand and gently stir through one of your chopped Mars Bars before pour the cheesecake mixture over the biscuit base and top with the remaining Mars Bar pieces.
Place in the fridge to set. Ideally you want to leave this overnight, but is should be ok after 6 hours.
Remove the set cheesecake from the fridge and serve.