Method

• 1.
  Preheat oven to 130°C. Line a large oven tray with baking paper. Scatter the white chocolate evenly over the tray and roast for 10 minutes, then remove and stir. Return to the oven and roast, stirring and pressing every 5 minutes, for 25 minutes or until dark golden and caramelised. (Don’t worry if the chocolate seizes as it will come back together in the following step.)
• 2.
  Transfer roasted chocolate to a heatproof bowl set over a saucepan of simmering water (don’t let the bowl touch water), stirring and pressing for 8-10 minutes until combined in a finely textured paste. Remove from the heat, cool to room temperature.
• 3.
  Increase oven to 160°C. Grease the base and side of a 22cm springform cake pan and line the base with baking paper.
• 4.
  Place biscuits in a food processor and whiz until fine crumbs, pulse in butter and peanuts. Press mixture evenly into base and side of prepared pan, chill until needed. Wipe out food processor.
• 5.
  Place cream cheese in the processor and whiz until smooth. Add sour cream and whiz to combine. Add eggs, yolk, caster sugar and cooled roasted white chocolate, and whiz to combine. Pour into pan and place on an oven tray. Bake for 1 hour 20 minutes or until just set with a gentle wobble in the centre. Turn off oven and cool completely in the oven, then chill for 4 hours or until firm and set.
• 6.
  For the brittle, line a baking tray with baking paper and place on a wire rack. Combine sugar and 1/3 cup (80ml) water in a small heavy-based saucepan over low heat. Cook, stirring constantly until sugar has dissolved. Stir in the glucose then increase heat to medium and bring to the boil. Boil, without stirring, until the mixture reaches 130°C on a sugar thermometer. Stir in peanuts and simmer, stirring occasionally, until mixture reaches 150°C. Remove from heat. Add butter, salt and stir in bicarb soda until well combined. Pour into prepared tray and, using a knife, spread into a thin layer. Set aside to cool completely then crumble. Scatter over cheesecake to serve.