Heat a pan on medium flame and add oil.
Once the oil is hot, add fenugreek seeds and allow them to crackle lightly. Do not burn them, as this can make the kulambu bitter.
Add sambar onions, curry leaves, and slit green chilli.
Saute well, stirring occasionally, until the onions turn golden brown and release a nice aroma.
Add the chopped tomatoes and mix well.
Cook until the tomatoes become soft and mushy and blend well with the onions. This helps form the base of the kulambu.
In a small bowl, add 2 tablespoons of homemade kolambu masala powder and mix with a little water to make a thick paste (masala ball).
Add this masala paste to the pan.
Add turmeric powder and salt.
Saute everything well on medium flame until the raw smell of the masala completely disappears and you see oil separating from the mixture. (This is a very important step and gives the kulambu its deep flavour.)
Pour in the tamarind extract and add required water depending on how thick you want the kulambu.
Mix well and let it boil for 5–7 minutes so the flavours combine nicely.
Gently add the cleaned ayila meen fish head pieces into the boiling kulambu.
Cover and cook for about 10 minutes, or until the fish head pieces are fully cooked.
Since fish head takes a little longer to cook, adjust the time if needed.
Switch off the flame and sprinkle chopped coriander leaves on top.
Cover the pan and let the kulambu rest for 10 minutes. This resting time helps the flavours settle and taste better.
Serve hot with steamed rice.
This ayila meen kulambu tastes even better when paired with a crispy fish fry on the side.