wash and soak dal in water for 15 minutes. Cook the dal in a pressure cooker for 3 whistles.
In the meantime take a pan, add oil and fry the onions. Add haldi powder.
After they become a little soft, add 3 cups of water.
Let the onions get cooked completely. Then add the sambar powder and salt. Let it boil for 4-5 minutes.
Now add the tamarind paste or pulp in 1 cup of water into the mixture.
Also by now, the dal would be ready to take out from the cooker.
Mash it till smooth and add it to the mixture.
Mix it nicely and bring it to a boil.
For seasoning, take a small pan, heat oil.
Add rai, methi seeds. When they splutter, add curry leaves, red chillies, and hing. Switch off the flame.
Pour this into the sambar mixture.
Stir it and let it simmer for 2-3 minutes.
Serve with steamed rice, idli, dosa or vada.
Onion Sambar Recipe https://tastyhealthyfoodrecipes.com/onion-sambar-recipe/