Place the shallots, ginger, coconut, and as little water as necessary into a blender, and blend to a fine paste. Set aside.
Heat the mustard oil on medium heat in a wide pan. Add the onion, sprinkle with salt, and cook for ten minutes or until the onions are soft and beginning to colour.
Add the whole cumin seeds and chillies, then stir continuously for two minutes.
Stir in the carrots, sweet potato, and potatoes, then add the turmeric and curry leaves. Mix well.
Cover the pan and cook over low heat, for 25 minutes, stirring often. If necessary, add a little water to prevent the vegetables from burning. Do not add too much water as the consistency of this dish should be quite dry.
When the potatoes are soft, add the beans and capsicum and stir through. Cook for another five minutes or until the beans have softened slightly.
Add the reserved shallot paste to the pan and stir through. Add the peas and cucumber, cook for a further five minutes, stirring thoroughly, being careful not to break up the whole vegetables.
Stir the yoghurt into the pan, one spoon at a time, mixing well before adding the next spoon. Allow to warm through, but not come to the boil as it will split.