Heat the oil in a frying pan on the hob and gently fry the chicken, stirring, until pale golden. Stir in the onions and fry for a further 5 minutes. Add the garlic and curry paste and fry for a further 1 minute.
Stir in the remaining ingredients, season with salt and bring just to the boil. Transfer to a casserole dish and cover with foil. Place the casserole dish on the lower rack of the halogen oven.
Set the temperature to 200°C (392°F) and cook for 25 minutes or until the chicken is cooked through. Garnish with coriander leaves and serve with warm naan bread or chapattis and wilted spinach.