Heat the oil in a casserole dish and fry the onion for 10 mins until beginning to soften. Add the garlic, ground coriander and coriander stalks, and cook for 1 min. Stir though the tomatoes, stock and chipotle and bring to a simmer. Cook, covered, over a low heat for 20 mins, stirring occasionally.

Meanwhile, bring a pan of water to the boil and cook the corn for 4 mins. Drain and leave to cool a little. Cut the kernels off the cob with a sharp knife. Heat a non-stick frying pan over a high heat. Add the corn and fry for 5-7 mins or until charred, stirring now and again.

Ladle the soup into bowls. Top with the feta, yogurt, charred corn and coriander leaves.