Turn your oven to 180?C/160?C fan/gas 4
To make the crumble combine all the ingredients together in a bowl and using your fingers rub the butter into the flour and sugar, so that the mixture comes together to form large breadcrumbs.
Place on a baking sheet and bake for 10 minutes
At the same time, place the cut up rhubarb into a baking dish and mix in the stem ginger and syrup.
Roast in the oven for about 30 minutes. The rhubarb should be soft but still firm.
Allow to cool and then chill in the fridge.
In a bowl mix together the soft cheese, yoghurt, oil, vanilla and salt and stir until smooth.
Pour into your ice-cream maker and churn until the mixture starts to thicken. At this point pour in the chilled rhubarb and ginger.
Spoon the mixture into the plastic freezer box and stir in the crumble pieces. Put the lid on and freeze for a minimum of 2 hours, or until the ice cream is firm enough to serve.