Heat oil in a saucepan, add mustard seeds, cumin and curry leaves.
When seeds pop, add onions, green chilies and saute until onions are soft.
Add garlic and let roast for few seconds.
Throw in salt, chili powder and turmeric. Mix well.
Pour the tempering over cooked dal, cover and let boil for few minutes.
Taste and adjust the seasoning.
Garnish with cilantro and serve.