1. COMBINE the biscuits and butter and press into the base of a lightly greased and lined 24 cm springform pan (ensure paper extends 5cm above the top of the pan).
2. PLACE the sugar and water in a saucepan and stir over a medium high heat until sugar has dissolved. Continue cooking, without stirring, until deep golden. Carefully add the cream mixture and stir to combine. Remove from the heat and then stir in the bourbon. Add the chocolate and stir until melted and smooth. Cool slightly.
3. BEAT the PHILADELPHIA with an electric mixer until smooth. Add the eggs and beat until combined. Stir in the melted chocolate mixture. Pour the filling into the prepared base.
4. BAKE in a slow oven 140°C for 50-60 minutes or until just set in the middle. Cool in the oven with door ajar. Chill.
5. TOP the cheesecake with marshmallows and cook under a preheated grill until soft and golden. Serve sliced with a drizzle of chocolate sauce.