Baked rhubarb and orange cheesecake

Method

1. Preheat the oven to 110°C/fan 90°C/gas ¼. Wipe the rhubarb stalks clean, trim off the ends and cut the stalks into 5cm pieces. Peel 3 wide strips of zest from the orange and cut them into fine slivers (like pine needles). Halve the orange, then squeeze out and reserve the orange juice.
2. Spread the rhubarb over the base of a large roasting tin and scatter over the orange zest, sugar and orange juice. Cover the tin tightly with foil and bake for 1½ hours. Meanwhile, remove the cream cheese from the fridge and leave it to come to room temperature.
3. Remove the rhubarb from the oven, uncover and carefully lift the pieces onto a baking tray with a fish slice. Leave, slightly raised at one end, to cool and drain. Strain the cooking juices from the roasting tin into a small pan and set aside.
4. Increase the oven temperature to 180°C/fan 160°C/gas 4. Line the base of a 23-24cm springform cake tin with baking paper. For the base, melt the butter in a medium pan, then stir in the crushed biscuits and demerara sugar. Spoon into the tin and press onto the base (not up the sides) in a thin, even layer. Bake in the middle of the oven for 10 minutes, then remove and leave to cool. Increase the oven temperature to 240°C/fan 220°C/gas 9.
5. For the topping, grease the sides of the tin with a little butter. Scoop the cream cheese into a large mixing bowl and beat with a hand-held electric mixer for 2 minutes until smooth and creamy. Beat in the 250g caster sugar, flour, salt, orange zest and juice, followed by the eggs, one at a time, then the yolk. Stir in 200ml soured cream.
6. Pour the cheesecake mixture into the tin, bake for 10 minutes, then lower the temperature to 110°C/fan 90°C/gas ¼ and bake for a further 30-35 minutes until just set but still quite wobbly in the centre. Turn off the oven, open the door slightly and leave the cheesecake inside to cool.
7. When the cheesecake has cooled, set it aside and preheat the oven to 150°C/fan 130°C/gas 2. Mix the rest of the soured cream with the remaining 1 tbsp sugar and the lemon juice. Arrange most of the drained rhubarb in a single layer over the top of the cheesecake. Spread the soured cream mixture over the top of the rhubarb, then return the cheesecake to the oven for 20 minutes. Remove and leave to cool once more, then cover loosely and chill for at least 8 hours or overnight. Add the juices from the baking tray to the rhubarb cooking juices in the small pan and boil rapidly for 5-6 minutes until slightly reduced and syrupy. Leave to cool, then pour into a small jug and chill alongside the cheesecake.
8. To serve, run a round-bladed knife around the sides of the tin to release the cheesecake, then carefully remove it from the tin. Drizzle over a little of the syrup, then serve cut into wedges with the remaining rhubarb and a little of the syrup spooned around.