1. COMBINE the biscuit crumbs and butter. Press into the base of a greased and fully paper lined 24cm springform pan (ensure the paper extends 5cm above the top of the pan). Chill.
2. BEAT the PHILLY, caster sugar and vanilla with an electric mixer until smooth. Add the cream, chocolate and eggs and mix until just combined. Pour over prepared base. Bake in a moderately slow oven 160°C for 45–50 minutes or until just set. Cool in the oven with door ajar. Chill.
3. COMBINE the sugar and water in a saucepan and stir until the sugar has dissolved. Bring to the boil and boil for 5 minutes. Add the orange slices, reduce the heat and simmer for 5 minutes or until tender. Remove oranges from the syrup and allow both to cool to room temperature.
4. DECORATE the cheesecake with orange slices. Slice and serve with a drizzle of orange syrup.