This comforting soup is wonderfully creamy, with warm and satisfying hits from coriander, cumin and, most importantly, fresh turmeric. When in season, fresh turmeric is available from many supermarkets and Indian grocery stores, and you may well be able to find it online. You could use ground turmeric for this recipe if you can’t find fresh, but bear in mind its flavour is more powerful than that of fresh. The lentils and chicken work very well together, but if you prefer you can make a vegetarian version by omitting the chicken and doubling the quantity of lentils. And, as a change from soup, you could try this dish with rice and a dollop of yogurt on top.