The curious rhubarb, powerfully sour when raw but when cooked with enough sweet element (such as sugar, maple syrup and honey), it balances pleasingly between sweet and tarty, silky and almost additive. I know this lanky vegetable is not everyone’s cup of tea, its intense tanginess (without cooking it right) is somewhat off-putting. My friend’s mother whom I dined with last week, while we were devouring this rhubarb apple crumble I made, told me that she never likes rhubarb because it is too sour, but she was impressed by this dessert, particularly, the combination of apple and rhubarb. She has even asked me for the recipe. This recipe is adapted from the British classic rhubarb crumble recipe I came across on Jamie Oliver’s website. Though the addition of apple is purely spontaneous, since I had two Gala sitting on the kitchen worktop for a few days and needed to be eaten urgently, so I didn’t hesitate to add them to the dish. I was almost certain that they would give an extra fruity note to the dessert. It turned out that the sweetness of the apple …