In a deep pan, heat the oil and sweat down the onions, carrots and celery for about 10 minutes. Stir in the garlic and ginger paste, curry paste, salt and pepper and fry for one minute. Pour in the coconut milk and chicken stock and bring to a boil. Turn the heat down to a medium simmer and add the apple and chicken. Cook until the apples are just tender but holding their shape. About 10 minutes.
Sprinkle with coriander and serve with basmati rice. and naan bread.