Wash and cut top of brinjals but do not peel.
Dice and stand in bowl liberally sprinkled with coarse salt for 10 minutes, then drain and wash dry.
Soak the coconut in warm water for 1/2 hour then, squeeze out well and use the milk.
Slice the onions, dice the green peppers and crush the garlic.
Heat the oil in a heavy pan and fry the onion and garlic very gently until golden.
Add the curry powder as the onions begin to soften, with the salt, pepper and mustard.
Add the brinjals, green peppers and cook for 5 minutes, then stir in the coconut milk, enough to moisten the mixture well.
Cover and simmer for 15 minutes, then add the sugar and vinegar, stirring in gently.
Cover and simmer for further 25 minutes.