Vanilla cheesecake with blood oranges and caramel

Method

1. Lightly oil the cake tin. Whizz the biscuits and hazelnuts in a food processor until very finely ground. With the motor running, pour in the butter with a pinch of salt, then whizz until the mixture looks like wet sand.
2. Tip some of the mixture into the oiled cake tin. Using your fingers and a metal spoon, flatten the biscuit mixture onto the base, then start to build up the sides, adding extra mixture and working it up the tin to form thin walls. Once you’ve used up all the mixture, chill the base in the fridge. Heat the oven to 160°C/140°C fan/gas 3.
3. To make the filling, put the cream cheese, mascarpone, soured cream, vanilla paste and 175g sugar in
4. a mixing bowl and whisk with an electric mixer until smooth and runny. Whisk in the eggs, then sift over the plain flour and whisk that in. Pour the mixture into the chilled biscuit case, then transfer to the oven, on a baking sheet, and bake for 50-60 minutes until set around the edges with a good wobble in the middle. Remove from the oven, cool and chill overnight.
5. For the topping, cut off the orange peel with a sharp knife, then cut out the segments, reserving the juices – it’s best to do this over a sieve in a bowl. Put the sugar in a heavy-based pan and heat very gently until the sugar has dissolved – don’t stir it. If it starts to caramelise too quickly in patches, use a fork to disperse the patches and redistribute the sugar. Once the sugar’s melted, turn up the heat slightly and cook to a rich golden-red caramel. Remove from the heat quickly and stir in the butter and liqueur. It will spit, so be careful. Add the salt, then stir in the cream.
6. Transfer the caramel to a bowl, add 3 tbsp reserved juice from the oranges, then leave to cool (you can add more juice if the caramel sets too firmly as it cools). Tip the orange wedges onto a few layers of kitchen paper, then pat gently with more kitchen paper to dry them slightly.
7. Remove the cheesecake from the fridge 30 minutes before serving. Ease it out of its tin – if it resists, either run a mini blow-torch round the edge or put it very briefly into a warm oven to soften the butter in the crust. Transfer to a serving plate. Just before serving, pile the orange wedges on top, drizzle over the caramel, then slice and serve.