Place the biscuits in the food processor and blitz to a fine crumble, or place them in the zip lock bag and crush using the rolling pin. Melt the butter in a saucepan. Pour the butter over the crushed biscuits while the food processor is running and mix well.
Place the cake rings on a tray lined with baking paper. Use a tray that will fit into the fridge. Tip the crumb mixture into the cake rings. Press firmly. Put in the fridge until needed.
Beat the cream cheese with the sugar and vanilla extract until smooth. In another bowl, beat the cream until stiff and then gently fold through the cream cheese. Spoon this onto the biscuit base and smooth the top. Leave the rings in the fridge to firm up for at least two hours.
Halve the passion fruits and scoop out the flesh with a spoon. Remove the rings and divide the passion fruit over the cheesecakes. Mini cheesecake with passion fruit.
