The day before you are making the cheesecake zest the orange on top of the curd cheese but do not mix it in. Cover. Squeeze the juice of the orange into a small bowl, add the raisins and leave them to soak overnight.
The next day generously butter a 23 cm springform cake tin and line the base with baking parchment. Butter the parchment. Preheat the oven to 160 C, 140 Fan Gas 3.
In a large bowl beat the curd cheese or ricotta with the orange zest until smooth. Beat in the cream cheese until well combined. Fold in the melted butter, semolina, orange flour water and salt. Drain the raisins and fold them into the mixture.
Spoon everything into the prepared tin and smooth the top with a spatula. Pour over the soured cream and smooth it into an even layer.
Place the tin on a baking sheet and bake the cheesecake for 35 to 40 minutes until it is set but still has a little wobble in the middle. It should be slightly pulling away from the sides and turning very lightly golden on top. It will set more as it cools.
Let it sit in the tin for 15 minutes before gently loosening the catch and sliding it on to a plate, carefully removing the parchment as you go. Serve warm or cold, on its own or with some more sour cream on the side, or with fruit.