Apple and rhubarb are a match made in heaven that's even better in crumble form!
Combine all ingredients of the apple and rhubarb mix in a pot on a medium heat for approximately 20 minutes or until soft. Drain any excess liquid, or add a tbsp of gelatin to thicken the remaining juices, and place into a baking tin. Set aside to cool.
Preheat oven to 180 degrees Celsius.
Combine all of the crumble ingredients into a bowl and mix well with fingers.
Place the crumble mix on top of the apple and rhubarb and place in the oven for 30 minutes or until the crumble darkens and becomes crispy.