Heat the oil in a large saucepan, add the garlic, coriander stalks and lime zest, then fry for 2 mins until fragrant. Stir in the cumin and chilli flakes, fry for 1 min more, then tip in the tomatoes, beans and stock. Bring to the boil, then crush the beans against the bottom of the pan a few times using a potato masher. This will thicken the soup a little.

Stir the kale into the soup, simmer for 5 mins or until tender, then tear in the chicken and let it heat through. Season to taste with salt, pepper and juice from half the lime, then serve in shallow bowls, scattered with the feta and a few coriander leaves. Serve the remaining lime in wedges for the table, with the toasted tortillas on the side. The longer you leave the chicken in the pan, the thicker the soup will become, so add a splash more stock if you can’t serve the soup straight away.