Clean and cut the luffa into 1 inch cubes. Clean garlic and shallot by removing dry skins.
Dry roast the green gram and keep it aside.
In a pan heat oil; add cumin seeds, mustard seeds, split bengal gram, split black gram, once the mustard seeds stop splattering add shallot, green chili, garlic, curry leaves, cumin seeds, coriander seeds and sauté until shallot turns translucent (golden brown).
Now add the tomato, luffa (Peerkangai) and mix once.
Now add the green gram, 750 milliliter of water, salt to taste and cook for 6 whistle and put the flame down.
Once the pressure is gone, mash the koottu with a masher (mathu refer image below). If there is excess of water simmer and cook until the right thinness is reached and serve.