Chop up the rhubarb and mix with the sugar/sweetener and cornflour
Pop into a greased dish (1pt oval dish, medium sized)
Mix the plain flour, oats and brown sugar/sweetener into a large bowl
Soften the butter and rub it into your dry ingredients until lumpy
Pop the crumble on top of the chopped rhubarb
Cook for approximately 40-50 minutes at 180°C fan
Serve warm with a generous helping of custard
