Peel, then finely chop the onion, garlic, ginger and turmeric.
Chop the sweet potatoes, red pepper and carrot into bite-sized chunks. Chop the tomatoes.
Heat the oil in a large pan. Gently sauté the onion for 5 minutes, then add garlic, ginger, turmeric and mustard seeds. Stir for a minute, then add the chopped vegetables, tomato purée and spices. Stir for a minute and add the chopped tomatoes and star anise. Cover and gently cook for another 5 minutes.
Add enough water to cover the vegetables. Season with salt and pepper.
Bring to the boil, cover and gently simmer over low heat for about 25 minutes until the vegetables are tender.
Add the chickpeas and spinach/kale, bring to the boil again and cook for 5 minutes to warm through.
Serve with chopped coriander leaves scattered on top.