Line the base and sides of a 23-24cm springform cake tin with baking parchment. To make the base, rub together the flour, sugar and spices in a large mixing bowl, making sure there are no lumps of sugar.
Heat the butter, golden syrup and treacle in a small saucepan until just boiling, then pour into the dry ingredients, mixing to a smooth dough. Press evenly into your cake tin, then bake for 10-12 mins until golden. Leave to cool.
To make the poached rhubarb, put the sugar, orange juice, ginger and syrup in a large pan and cook until just dissolved.
Add the rhubarb, cover with a lid and poach on the lowest possible heat for 5-7 mins until just tender.
Using a slotted spoon, remove the rhubarb and stem ginger to a plate, being careful not to damage the shape. Increase the heat and reduce the liquid for a few mins until just syrupy. If you like, add a splash of grenadine to make a bright pink syrup. Using a fork, crush half the poached rhubarb with enough syrup to give a thick compote. Stir in the whole pieces and set aside to cool completely. Reserve the remaining syrup to serve.
In a large mixing bowl, mix the cream cheese, soured cream, sugar and cornflour.
Whisk in the eggs, yolks, orange zest and vanilla until evenly combined, then pour into the tin. Dot spoonfuls of the cold rhubarb compote over the filling with a little extra syrup and ripple through with the back of a spoon.
Bake for 10 mins. Reduce oven to 120C/ 100C fan/gas and bake for 50-55 mins more. Turn off the oven, keep the door closed and leave the cheesecake for 1 hr. Open the oven door a little, keep it ajar with oven gloves and leave for a 1 hr more.
Remove and leave at room temperature until completely cool, then chill overnight.
To serve, remove from the tin and carefully remove the baking paper. Slice and serve with the reserved syrup.
