The arrival of naartjies in the supermarket signals that winter has arrived.  A firm favourite among South Africans, naartjies are known as mandarins or tangerines in other parts of the world.  Considering their abundance at this time of year, I felt it would be unthinkable not to create a delicious recipe using them. It was not hard to do so. I mean, what's not to love about their bright, glossy peel and juicy, sweet flesh? Keeping with a South African theme, I incorporated the fruity notes of Rooibos tea. The resulting cake is dense, citrusy and utterly "lekker". Baking it in a...