Using root vegetables in baking isn’t new. Carrots and parsnips are some of my favourites to play around with, but sweet potato has its place, too. It brings such a pleasant squidginess and earthy flavour that just sings autumn. Roast the potatoes in their skins, then scoop out the flesh or, for something quicker, just stick them in the microwave; I’d avoid boiling them, though, because that introduces too much extra water. This is a proper cosy cake, one that requires a good tea in your biggest mug.
