Finely slice the onion, garlic & ginger, then the mushrooms and green pepper.
Heat the oil in a saucepan, then gently sauté the onion for about five minutes, until softened.
Add the garlic and ginger, stir for a minute, then add the mushrooms. Put a lid on and sauté for 5 minutes, then add the curry powder.
Stir for a few seconds, then add the tomato purée and stir again.
Add enough water to cover it, bring to the boil, then cook for 10 minutes.
Add the beans and the coconut milk - you might need to add some more water to cover all. Season with salt and pepper and cook over low heat for another 5-10 minutes.
Serve with chopped coriander leaves and lime juice stirred through.