Caramelised white chocolate cheesecake

Ingredients

For the base

• 300g Nice or digestive biscuits
• 170g unsalted butter, melted

For the filling

• 250g white chocolate, roughly chopped
• Salt
• 680g full-fat cream cheese, at room temperature
• 100g caster sugar
• 3 large eggs, plus 2 egg yolks
• 240g soured cream, at room temperature

For the topping

• 200g rhubarb, washed, trimmed and cut into 2-3cm chunks
• 30g caster sugar
• ½ tsp vanilla extract

Directions

1. To make the caramelised white chocolate, heat the oven to 140°C (120°C fan). Put the chocolate on an oven tray, bake for 10 minutes, then stir until smooth. Return the chocolate to the oven for a further 60-70 minutes, repeating the stirring process every 15 minutes. At some points, the chocolate will look quite grainy, but keep stirring to get it back into a liquid state. Once the chocolate turns a light caramel colour, stir in a pinch of salt and leave to cool.
2. Meanwhile, line the base and sides of a 20cm loose-bottomed cake tin and turn the oven up to 160°C (140°C fan). Finely crush the biscuits in a food processor (or put them in a plastic bag and bash with a rolling pin or similar). Stir in the melted butter, then tip the biscuit mix into the lined tin and use the back of a spoon to press it tightly into the base and up the sides. Chill while you make the filling.
3. If the caramelised chocolate has set, melt it in the microwave, then leave to cool a little. Put the cream cheese, sugar and a quarter-teaspoon of salt in a large bowl and mix until smooth. Add the whole eggs and egg yolks, mix well, then stir in the soured cream. Pour in the melted chocolate, stir until smooth, then pour into the tin.
4. Wrap the base and sides of the tin in two or three sheets of tinfoil, put it on a larger baking tray and pour in enough boiling water to come halfway up the sides of the cake tin. Bake for 75-85 minutes, until the edges look set but there’s a good wobble in the middle. Remove the cheesecake from the water bath and leave to cool to room temperature. Transfer to the fridge to chill for at least three hours.
5. Meanwhile, put the rhubarb in a wide, shallow pan with the sugar and vanilla, and macerate for 10 minutes. Add 85ml cold water, bring to a simmer and cook gently over a medium heat for three to five minutes, until the edges of the rhubarb start to soften but still hold their shape. Leave to cool in the pan. (You can make this in advance and store in the fridge; the longer the rhubarb sits in the poaching liquid, the brighter its colour will be.)
6. To serve, carefully unclip the cheesecake from its tin, top with the poached rhubarb and slice.