Preheat oven to 140ºC (no fan or low fan). Line a 24cm springform tin with baking paper. Crush biscuits with a rolling pin or in a food processor until you have a fine crumb.

Put biscuit crumbs in a mixing bowl, add melted butter and mix with a wooden spoon until well combined. Press crumb mixture into the base of prepared tin and press firmly with the back of the spoon.

Put cream cheese, eggs and sugar in a large bowl and beat with electric beaters for 4-5 minutes or until the mixture is very smooth.

Put white chocolate and cream in a medium heavy-based pan and stir over a low heat until the chocolate is melted and mixture is smooth. Add the white chocolate mixture to the cream cheese mixture in a thin stream and beat with electric beaters on low until mixture is well combined.

5 Pour the mixture into the biscuit base. Gently tap the tin on the bench a few times to knock any air bubbles out of the mixture, to ensure a smooth finish. Bake cheesecake for 1-2 hours or until the mixture is set.

When set, remove the cheesecake from the oven to cool on a rack. When cool, put the cheesecake in the fridge and chill for 1 hour. When cold, remove from the fridge and sit the rack over a plate or tray larger than the cake.

Put dark chocolate and extra cream in a medium heavy-based pan and stir over a low heat until the chocolate is melted and the mixture is smooth. Pour the chocolate and cream mixture over the cheesecake and let it run down the sides. Cut the cheesecake into wedges and serve.