Soak toor dal for 2 hrs,in a mixer,first grind jeera,fennel seeds(if desired),red chillies,coconut to a coarse powder.
Then add the toor dal (soaked,water drained )and grind coarsely.(little bit finer than we grind for masala vada)(don’t add water)Add chopped onions,salt,coriander leaves and mix well.
Make small balls out of the ground batter and steam it by placing in a greased idly plates and steam it for 10 to 12 minutes.Cool down a bit(but let it be still warm),and again shape tightly,to make it perfect shaped koftas. SKIP this step if adding directly.
Extract tamarind juice,keep a side,grind the coconut and onion for a fine paste,keep a side.Heat a kadai,with oil and add the tempering items under the tableTo temper. Add garlic,onion and fry till golden brown.Then add the chopped tomatoes and fry for a minute.
Add the tamarind extract,sambar powder,turmeric and bring to boil. Mean while grind coconut with little water and onion to a paste.
Add to the boiling kuzhambu and let it boil for 5-6 minutes.Lower the flame and add the urundais one by one carefully.
Boil in medium flame until all the balls float on the top(6 mins approx),by this time it would have got cooked.Do not stir till this stage. simmer for 4 mins and the kuzhambu is ready!