Pour idli batter into greased moulds and steam for 10-12 minutes.
Boil yellow lentils with turmeric powder and water until tender.
In a pot, cook drumstick pieces and chopped tomato with tamarind paste, sambar powder, and salt.
Combine cooked lentils into the stew and simmer for 5 minutes.
Temper mustard seeds, curry leaves, asafoetida, and dry red chili in oil and pour into sambar; serve over hot idlis.