To make the bases:
Place 8 metal ring moulds of approximately 6-7 cm diameter on a baking tray. Combine together the biscuit crumbs and melted butter. Divide the mixture between the moulds and press firmly into the bases. Chill well whilst preparing the filling.

To make the caramelized apples:
Toss the diced apple in the lemon juice to prevent browning. Set aside. Spread just 125 g of the sugar evenly over the base of a heavy based pan. Heat the sugar over a medium heat, watching all the time. The sugar will start to liquefy at the edges. Once the caramel starts to brown at the edges, drag towards the centre. Try to avoid stirring but gently and carefully swirl the pan by the handle to mix. As soon as a uniform amber colour is reached, remove the pan from the heat. Carefully add the butter. It may spit so be mindful. Then stir in the drained apples. Cook the apples in the caramel for just a few minutes until lightly cooked.

To make the filling:
Soak the gelatine in a bowl of cold water until softened, then drain well. Meanwhile heat the apple juice until warm. Add the softened gelatine and stir until melted. Mix together the Philadelphia and remaining 85 g sugar until smooth. Gradually whisk the gelatine apple juice into the Philadelphia mixture and then fold in the whipped cream. Divide about a third of the cheesecake mixture between the 8 moulds. Top with about a third of the caramelized apples and repeat again. Finish with a layer of cheesecake mixture and smooth the surface and then scatter over the remaining third of apples. Refrigerate for 3 hours to set.

To decorate:
Just before serving, remove the cheesecakes from the moulds by warming the moulds slightly with a warm damp cloth and pushing gently up from the bottom. Decorate each cheesecake with some popcorn and if liked, some salted butter caramel sauce.