It must be made the day before. It is basically as home made swiss roll mixture cooled and spread with cooked rhubarb, vanilla ice-cream shaped into a long sausage- then rolled up and frozen.If you have an ice-cream machine then make a vanilla batch, otherwise buy good quality dairy vanilla ice cream. Allow the ice cream to soften slightly then on a sheet of non-stick paper scoop it into a long sausage shape and roll up. Cover with cling film and return to the freezer. Ideally do this in advance.
Next the rhubarb. Prepare 400g rhubarb – wipe and cut into 2cm lengths, sprinkle over 100g caster sugar and bake at 150°C for 20 minutes. Allow to cool. Add 50g chopped crystallised ginger if you prefer.