Cook Toor dal ina pressure cooker. Grind coconut and cumin in a mixer.
Cut ash gourd into small pieces of about 2 inches. Boil water and add ash gourd, turmeric and salt and let cook. When almost done, add toor dal and ground coconut-cumin mixture. Stir well and let ithe mixture boil. Turn off the heat.
Heat oil in a frying pan and add mustard seeds. Let it splutter. Now add green chili, onion and curry leaves. Roast well and pour it onto the prepared curry.