Grind the urad dal with very little water into a smooth batter. Add salt and beat well till light and fluffy. Grind the cumin seeds, peppercorns and garlic into a smooth paste. Keep aside.
Heat oil in a pan and drop spoonfuls of the batter into the hot oil. Deep fry them to a golden colour. Drain and keep aside.
Pressure cook the soaked dal and tomatoes in 3-4 cups water for 4-5 whistles. After it cools down, blend it in a mixi. Strain and keep aside.
Heat 2 tbsp. oil and temper with mustard seeds. asafoetida and curry leaves. Saute for a few seconds and then add the ground paste and turmeric powder. Stir fry till the oil separates.
Add the tomato water and salt. Bring it to a boil and simmer for 2-3 minutes. Switch off the flame and add the ghee.
While serving, dip the vadas in the rasam and serve, garnished with coriander leaves.
