Soak the mustard seeds and poppy seeds in warm water for 20 odd minutes. Using an electric blender, blitz the mustard and poppy seeds and 2 green chillies to a fine paste. Keep aside.
Heat 1.5 tbsp oil in a pan, throw in the kalonji and 2-3 green chilies. When the kalonji starts to splutter, add the ridgegourd cubes.
Add a little salt, cook over a moderate flame till the water released by the ridgegourd almost dries up.
Stir in the mustard-poppy seeds paste, add the remaining green chilies. Sauté over a high flame for another 2-3 minutes.
Add the tender coconut flesh, continue to cook for a further 4-5 minutes. Add the sugar, adjust seasonings.
Finish with a generous drizzle of mustard oil. Allow to rest for 10 odd minutes.
Serve with rice.