Overnight soak the vaal or field beans in water. Next day, drain the water and keep aside. Heat oil in a pan and when it gets hot, add mustard seeds, cumin seeds, curry leaves, sliced onions and salt. Add hing, crushed green chillies, garlic, turmeric, red chilli powder and Malvani masala powder. Add vaal or field beans (soaked overnight in water) and mix thoroughly. Cover the pan with a lid and cook for around 15 minutes on slow flame or until the vaal is tender and soft. Once the vaal is tender, add finely grated coconut and mix well. Sprinkle coriander leaves on the top and switch off the flame.