Wash the ridge gourds thoroughly and peel them. Set aside this peel.
In a pan, roast the peel for 5min adding ½tsp oil (optional if you want to dry roast without oil) along with the green chillies.
Set the roasted peel aside and let it cool.
Dry roast urad dal and sesame seeds separately and set aside to cool.
Grind together urad dal and sesame seeds to make a powder.
To this powder add the roasted peel, tamarind, sugar and salt. Grind all of them together adding little water if required. Make a smooth paste.
In a pan, heat oil and add mustard seeds and let them splutter.
Add the dry red chilli and curry leaves to it and add this seasoning to the ground smooth paste.
Serve this chutney with steamed rice.