Line the base and sides of a tall 20cm round spring-form tin.
Place the gingernut biscuits in a food processor and pulse until they turn into fine crumbs (alternatively, use a rolling pin to crush them). Combine them with the melted butter, then transfer the mixture to the lined baking tin and press firmly and evenly into the base and sides to form a tart shell (use a flat bottom cup or ramekin to help you with this). Refrigerate the base while you make the filling.
In a large mixing bowl, cream together the softened cream cheese and icing sugar until well combined. Pour in the melted white chocolate and continue to beat on medium/high speed until smooth and fluffy (1-2 minutes). Set aside.
In another mixing bowl, combine the boiled water with gelatine, stirring constantly to remove any lumps. Set aside for a few moments to dissolve fully. Once dissolved, add the mango puree and lime juice and mix to incorporate.
Scoop ½ of the mango mixture into the cream cheese and whip to combine.
Add chilli salt and lime zest to the remaining mango mixture and mix well.
To assemble, pour the cheesecake mixture into the biscuit base and smooth off the top with the back of a spoon. Dollop spoonfuls of the salted mango puree into the cheesecake and swirl around for a marble effect. Place the cheesecake in the fridge for a minimum of 4 hors, or overnight, to fully set. Keep refrigerated until ready to serve. Decorate with extra fresh mango, if preferred.
