Soak bown chickpeas overnight and pressure cook. Peel the outer skin of plantain, cut into small pieces .
Heat oil in a pan, add mustard when oil is hot and let splutter. Then add cumin, chopped onions, green chillies and curry leaves. Stir fry in low heat until onion gets tender. Add cut plantain, red chilli powder, turmeric powder, water and salt and let cook. Now add cooked chickpea and keep stirring well until all water is evaporated.
Turn off the heat and stir in grated coconut. Transfer kootu curry to a serving bowl.