To make the coriander yoghurt, mix everything together and adjust the seasoning to taste.

Preheat oven to 160ºC.

Cut carrots lengthways into eighths, then cut each piece in half. Combine the carrots, half the cumin seeds and half the olive oil in a large baking dish. Roast for 1 hour, shaking the dish occasionally, or until carrots are tender and lightly browned.

Meanwhile, dry roast (without oil) the remaining cumin seeds in a small pan over a low heat until fragrant.

Using a mortar and pestle, crush the roasted seeds until finely ground.

Heat remaining oil and butter in a large, heavy-based saucepan. Add ground cumin, onion, garlic, ginger and salt. Sweat over a very low heat for about 10 minutes or until onion is very soft.

Add sugar and potatoes, cook, stirring, for a further 5 minutes on medium.

Add roasted carrots and chicken stock and simmer, covered, for about 30 minutes or until vegetables are very tender. Process with a stick blender until very smooth. Stir in cream and pepper.

Add more chicken stock if necessary to give the desired consistency. Divide between 4 large bowls and serve with a dollop of coriander yoghurt.

Photography by William Meppem. Food styling by Hannah Meppem. Food preparation by Nick Banbury.