You can skip this step if you have sambar powder ready. To make the powder, heat a pan and dry roast urad dal, chana dal and red chilies on a medium flame until lightly golden. Meanwhile if you see the red chilies turn crisp you can set them aside.
Then add coriander seeds and roast till golden. Then quickly add cumin or jeera. When they smell good remove to a plate. Then add methi seeds & roast. When the methi seeds begin to smell good & turn deep golden, turn off the stove.
Cool all of these and make a fine powder in blender jar.
Wash rice and dal together in a bowl or directly in the cooker. Then pour 2 cups of water & pressure cook them together on a medium flame. If cooking in a bowl cook for 3 whistles. If cooking in the cooker directly, then cook for 2 whistles.
When the pressure releases naturally remove the rice & dal & slightly mash them.
Heat ghee in a pan. Add cumin, mustard, red chilli & curry leaves. When they splutter and curry leaves turn crisp, add hing.
Next add veggies and saute for 2 to 3 minutes. Saute tomatoes along with red chilli powder, turmeric for 3 minutes.
Pour 1 cup water and cook the vegetables until soft.
Take some hot water from the pan to a bowl and soak tamarind in it.
Mash the soaked tamarind when it softens and remove the pulp. You can also filter the tamarind water.
Check if the vegetables are cooked especially the drumstick. When the veggies are almost cooked, pour this tamarind water, salt and sambar powder to the boiling veggies.
Cook until it begins to smell good for about 3 to 4 minutes. Next add the mashed rice and dal.
Stir well to blend the rice & dal in cooked veggies. Check the salt and spice. Adjust salt, sambar powder and tamarind as needed.
If needed add more water to bring to consistency. When it begins to bubble turn off the stove.
Serve sambar rice hot with papad or pickle.
If you prefer you can also do a additional tempering by heating another tbsp of ghee in a small tadka pan. Add a pinch of mustard, 1 broken chilli & curry leaves. When the leaves turn crisp, add hing & pour this to the sambar rice.