Heat a little oil in a pan and saute sliced onions in it. When they turn brown in colour add red chilli powder, coriander powder and salt and mix well. Add chopped tomatoes, chopped red and green chillies, and sliced bitter gourd and mix well in the masala. Add a little water and saute some more. Add some peanut powder and grated coconut to give the sabzi a good flavour. Let the bitter gourd cook well. When done, transfer it to a serving plate and garnish the sabzi with some grated coconut.