Soak the yellow lentils for half an hour. Wash thoroughly. Pressure cook with enough water till soft.
Soak rice for an hour. Drain the water and keep aside.
Take a thick bottomed pan. Roast all the ingredients for sambar masala and let them cool.
Heat oil/ghee in a deep bottomed pan.
Add the mustard seeds, cumin, red chillies, asafoetida, fenugreek seeds and curry leaves and sauté for a minute. Do not burn.
Now add onions and green chillies. Sauté.
Add all the vegetables one by one and cook on a slow flame while tossing intermittently.
Add salt, turmeric and cook on a slow flame with the lid closed.
Cook till the vegetables become soft.
Mash the dal and add it to the vegetables. Add 2 cups of water and mix well.
Once this water starts boiling, add the rice. Add some more water to it.
Cover the lid and cook on a slow flame till the rice is cooked. Check intermittently for the consistency. If needed add some more water.
While the rice is getting cooked, blend the dry masala ingredients.
Once the rice is cooked add the tamarind juice.
Let it boil.
Add the sabar masala powder and mix well.
In a pan heat one tsp of ghee and roast some cashews and mustard seeds and add it to the sambar rice.
Garnish with finely chopped coriander.