Dry roast peanuts till they have brown spots on their skin, keep aside. You can also roast the peanuts in the air fryer.
In the same pan take 1 teaspoon of oil, add onion and fry till light brown in color and then add garlic and saute for 30 secs. Turn off the flame.
In a blender add roasted peanut with skin, roasted chana (putani), onion-garlic sautéed mixture, tamarind, red chili powder, sambar/rasam powder, and grind it with water till smooth paste. Keep aside.
Now, prepare the tempering, in a kadai add oil, once hot add mustard seeds, jeera and let them splutter.Then add curry leaves, onion saute till onions turn soft. Switch off the flame. To the tempering add grounded peanut paste, turmeric powder, gurellu pudi, jaggery, coriander leaves, water, and salt. Mix well. Don't boil the sambar.
Shenga Saaru or Peanut sambar is ready to serve with Ragi Mudde or Rice.