Just remove the edges of the watercress stems n yellowish leaves n wash them thoroughly n keep aside. Heat 2 cups of water in a heavy bottomed pan, meanwhile wash thoroughly the moong dal n keep aside, add the washed moongdal to the hot water n cook for a while in medium flame, now add the roughly chopped onion followed by tomatoes, garlic pods n slit opened green chillies n close the lid n put the flame in simmer, after a while once the dal n veggies r well cooked add the well washed n roughly chopped watercress green n cook them for a while, as the watercress contains enough water n the stems r hollow, they will get cooked very easily, check whether they r cooked n put off the stove..heat the oil in a pan , once the oil is hot, add the vadagam r mustard seeds n urad dal n let the splutters, add the red chillies n fry them well, add this to the well cooked greens as well as the salt n mash them with a food processor r with a hand blender, will be very much perfect with a masher( mathu) as i dont have, i used hand blender..

Serve hot with rice n ghee (optional)..Enjoyyyy!!!!!!!!!!!