Very lightly grease the base and sides of a 23cm/9in springform cake tin approximately 5cm/2in deep. Stand the tin on a baking sheet.
Melt the butter in a small saucepan and allow to cool.
Preheat the oven to 190C/170C Fan/Gas 5.
Crush the biscuits to fine crumbs in a food processor, or place in a strong plastic bag and bash with a rolling pin.
In a bowl, mix the crushed biscuits with the melted butter until fully combined. Tip the mixture into the prepared tin and spread it out to form an even layer, pressing it firmly and uniformly with flattened knuckles.
Bake for 12 minutes, or until the base has firmed up like a pastry layer. Set aside on the baking sheet to cool.
Lower the oven temperature to 160C/140C Fan/Gas 3.
Using a swivel peeler, finely pare the zest of one orange in strips, then cut these into long, thin julienne.
In a small saucepan, dissolve 75g/2½oz of sugar in 100ml/3½fl oz of water over a medium heat, then bring to the boil.
Add the julienned orange zest, reduce the heat to a simmer and poach the zest in the syrup for 10 minutes. Remove from the heat and set aside to cool completely. One cooled, drain the julienned zest and discard the syrup.
Rub the skins of the remaining oranges against the finest grating surface of a box grater to produce a wet zest purée. Scrape into a small bowl and set aside.
Juice all the oranges, then strain the juice through a fine chinois or sieve.
Put the cream cheese, curd cheese, soured cream and remaining sugar in a large bowl and mix until smooth.
In another bowl, whisk the eggs until light and foamy, then strain through a fine chinois or sieve into the cream cheese mixture. Mix well with a wooden spoon, then add the orange juice and zest purée and mix to combine.
Spoon the mixture over the cooled biscuit base and bake for 1½ hours. Turn off the oven and leave the cheesecake inside for a further hour, with the door very slightly open. Remove the cheesecake from the oven and leave to cool completely. Once cooled, refrigerate for at least 2–3 hours before serving,
When you’re ready to serve, run a knife around the inside of the tin and gently release the sides of the tin. Carefully transfer the cheesecake to a serving plate.
Using a palette knife, spread the honey over the cheesecake. Sprinkle a little of the candied orange zest julienne on top and scatter over the pistachios.
Use a very sharp knife dipped in hot water to cut the cheesecake into slices, returning the knife to the hot water in between slices.