Heat the oil in a small saucepan or kadai
Add the mustard seeds to the oil and cover.
When the seeds are done popping, remove the lid, and turn down the heat.
Add the urad dal and green chilis and give them a quick stir.
Add most of the cilantro, reserving a little bit for garnish
Turn the heat off, the cilantro will wilt in the residual heat.
Pour the vaggarnae over the raita and garnish with the fresh grated coconut and the rest of the cilantro.
Chill the raita in the refrigerator until ready to serve.