This simple soup is flavoured with warm spices, then blended to a velvety smooth texture and topped with yogourt. Serve it as a fast and sustaining lunch with nan bread or other lightly toasted bread of your choice.
Heat the oil in a pot. Add the onion and cook over a low heat for about 8 minutes, stirring occasionally, until beginning to soften. Stir in the celery and carrot and cook for 3 minutes, stirring frequently. Add the garlic, cumin and coriander and cook for a further minute, stirring constantly.
Add the lentils, stock, tomatoes with their juice, tomato paste and bay leaf. Bring to a boil, reduce the heat, then half cover the pot with a lid and simmer for 25-30 minutes until the lentils and vegetables are very soft.
Meanwhile, to make the yogourt topping, stir the chopped cilantro into the yogourt.
Remove the bay leaf from the soup. Blend the soup in the pot using a hand-held blender, or tip into a blender or food processor, process until smooth, then return the soup to the pot. Check the consistency; it will be fairly thick, so if you prefer it thinner, dilute with a little more stock or some water. Season to taste, then reheat until just bubbling. Serve drizzled with some of the yogourt topping.
Cook's tip: If you are preparing the soup ahead of time, add the cilantro yogourt just before serving.
Variation: For a spicy lentil and parsnip soup, stir in 1⁄4 teaspoon chili flakes with the spices and add 250 grams (1⁄2 lb) roughly chopped parsnips instead of the celery.
Each serving: 7 g protein, 7 g fat of which 2 g saturates, 17.5 g carbohydrate, 5 g fibre, 173 Calories