Pour half the cheesecake mixture over the cooled biscuit base, then dot over half of the cooled blackcurrant sauce. Pour over the remaining cheesecake mixture, and carefully smooth the surface using a spatula. Drizzle over the remaining blackcurrant sauce, then gently ripple it through the cheesecake mixture using a skewer or the end of a spoon. Bake for 10 mins, then reduce the oven temperature to 110C/90C fan/gas ¼ and bake for a further 30 mins until set with a slight wobble in the middle. Turn off the oven and leave the cheesecake inside with the door closed for 1 hr, then open the door slightly and leave for 1 hr more. Finally, leave to cool completely at room temperature, then chill for at least 3 hrs or overnight before slicing. Will keep chilled for five days.
