Heat the butter in a deep frying pan, add the onion, then soften gently for 5 mins. Turn up the heat and add the ginger and spices; fry for 2 mins until fragrant. Stir in the tomato purée.
Add the kale, chickpeas (chana), stock and two-thirds of the coconut, stir well, then cover the pan. Bring to a simmer and let the kale steam for 10 mins until very well wilted. Mix in the yogurt and chutney, then season to taste - don't boil once the yogurt has gone in. Remove the pan from the heat, and leave it covered to stay warm.
Heat the oil in a small saucepan. When it's hot, add the garlic (and curry leaves, if using) and sizzle for 30 secs-1 min until the garlic begins to turn golden. Spoon the oil, garlic and curry leaves over the chickpeas and kale, then finish with the remaining coconut.