Apply some oil to both your hands and rub together ensuring both hands are well coated. Soak the moong lentils in some water and keep aside (for about 1/2 hour). In a largish bowl, pour the sour yogurt/ buttermilk and add another 2 to 2 1/2 cups or so of water and mix well. The chopped flowers are soaked in this to counter the bitterness as well as to prevent discolouration.
Peel off the first leaf and you will see an orderly row of small yellow tipped flowers at the base. If they look very dark and mature, discard them with the leaf. Peel off and discard the first few outer red leaves but keep the small yellowish white flowers. Trim the base of the flowers and remove the outer thin waxy layer. Then pull out and discard the stiff (sometimes dark) stamen from the centre of the flower. Chop the flowers and immediately immerse them in the diluted yogurt/ buttermilk
Once you reach the pale coloured and almost white coloured leaves, the flowers look soft and tender and peeling the leaves becomes difficult, you will find the stamens are very soft. Cut off whatever bit of stalk/ stem is present. You can stop removing them and the leaves and chop this up (leaves and flowers together). Now go wash your hands!
Let the chopped flower stay in the liquid for about an hour. You can even keep them overnight in the fridge (do the cleaning just before you go to bed) and then cook them in the morning.
To cook the flowers, drain the liquid and rinse the chopped flowers. Heat the coconut oil in a wok and add the mustard seeds. When they crackle, add the black gram lentils and stir a couple of time till they start turning brown. Add the asafoetida, curry leaves and green chillies and stir a couple of times. Drain the moong lentils of the water and add them to the wok. Add the chopped flowers and stir fry for a couple of minutes and turn down the heat to medium.
Add the turmeric powder and salt. Sprinkle a little water and allow t to cook, stirring occasionally and sprinkling a little more water if necessary. This dish cooks up very quickly. Once the lentils and flowers are cooked, turn off the heat. Add the grated coconut and mix well. Serve hot as a side dish with rice.