Generally, in any household, nothing is checked for the taste before offering to GOD. In Iyengar household, offering to bhagavan is said as 'kandarulap pannudhal'(கண்டருளப் பண்ணுதல்), which means everything cooked for the day is presented before bhagavan, so that he can mercifully glance them with his divine vision to purify the same. So, nothing is tasted while cooking.
But as the ingredients in this kuzhambu are already offered and tasted, you are at liberty to check for the taste and add salt, chilli powder or sambar powder if needed.
This kuzhambu has a unique taste. It can be mixed with hot cooked rice and ghee and goes well with adai, dosai, idlies too. Tastes excellent with curd rice. It is almost a forgotten grandma's recipe.
Some people say ezhu kari koottu/ thalagam which is made on Tiruvadhirai as erichcha kuzhambu. But this is different from that, with very little ingredients, heated and heated in oil until it becomes thick . Click here for ezhu kari koottu.
* DO NOT ADD* leftover raitha/thayir pachadi, sweet pachadi, payasam, pradhaman or anything which has jaggery or sugar, milk, buttermilk or curd in it.
Leftover kariamudhu(roast,curry/poriyal), kootu, sambar/kuzhambu, thogayal and rasam
Oil - one /two ladles or more depending on the leftovers