Cut the courgettes - wash them by all means if you want, but don't bother to peel them - into 5mm / one-eighth of an inch rings, and then finely dice them. Put them into a pan with the lemon zest and oil, stir to coat, then cook on a gentle heat for about 5 minutes, stirring occasionally, until they've slightly softened.Stir in the turmeric and pour in the stock and lemon juice and then drop in the rice. And for the stock here, as usual I make up some bouillon concentrate with water; you could use vegetable stock if you prefer, but I love the mellow goldenness you get from chicken.Cook, uncovered, for 10-20 minutes, or just until the courgettes and rice are tender. Taste for seasoning.Leave to cool slightly before serving so that you eat the soup warm rather than hot.