Mix the oil with the salt and cumin, coat the chicken pieces in the seasoned oil. Heat up the casserole dish, fry the chicken for approx. 3 mins. on each side.
Add the coconut milk, chopped tomatoes & sweet chilli sauce to the chicken, season with salt, bring to the boil. Stir in the spring onions, garlic and lemongrass, cover and cook over a medium heat for approx. 20 mins., stirring occasionally. Remove the lid and continue to cook for approx. 20 mins. Remove the lemongrass.
Shortly before serving, stir in the mango and coriander.