I have always loved crumble but I never make it at home as I know it calls for white flour, butter and sugar. So instead I have swapped this for oats, buckwheat flour, coconut oil and honey. Which makes it plant-based and a lot more nutritious, without compromising on taste.
The filling for this crumble is Rhubarb. But you can definitely experiment with the fruit you use, as all I had left in my kitchen to add some more natural sweetness was blueberries and an apple. So in terms of fruit filling you can definitely play around with that part.