Soak tamarind in 1 cup of warm water for 20 minutes. Now drain the water in a separate bowl by removing the pulp.

Clean and pressure cook pigeon peas lentil with 1 cup of water and turmeric powder till its soft and cooked properly. Mash the lentil with a ladle and keep it aside. 

Roast the channa dal, coriander seeds, red chillies, pepper corn for 2 minutes on low flame. Add freshly grated coconut and roast it till it turns light brown.

Allow it to cool down, add it to your mixer grinder and blitz it to make a smooth paste by adding little water to it.

Heat 1 tbsp oil in a sauce pan and add small onions. Stir fry till they turn translucent. Now add chopped radish and saute. Add tamarind water and let it simmer for few minutes till radish gets cooked.

Now add coconut paste, cooked lentil and 1/2 cup of water in a pan and let it simmer on low flame for few minutes.

Add salt to taste, jaggery powder and mix it well. If you feel its too thick, you can some more water and adjust the consistency.

Add oil in a small frying pan and when its warm add mustard seeds. When mustard seeds splutter, add curry leaves, asafetida and sauté for few seconds.

Add this tempering in sambar and serve it hot with some rice or Idli or dosa.