Clean and make 3-4 gashes on each side of the fish; pat-dry the cleaned fish using a kitchen tissue.
In a blender, add black pepper fennels seeds, garlic cloves, ginger piece, small onions, few curry leaves, turmeric, chili, coriander powder, and tamarind paste and blend it a smooth paste.
Add salt to taste and apply the masala paste on the fish and do make sure to rub the paste inside the fish's stomach and gashes.
Add the green chilies and curry leaves and combine well. Keep the marinated fish pieces for 30 mins to 1 hour in the refrigerator. (Note: The marination time purely depends on the time availability)
Heat the earthen pot on medium flame with Banana leaves and spread Banana leaves on the top and coat the banana leaves with 2tbsp of coconut oil.
Line the masala coated fish on the top of banana leaves.
Sprinkle curry leaves and 2 tbsp of coconut oil.
Cover with another piece of banana leaves and cook on medium heat until well cooked.
Traditionally, once sardines-mathi-chala is cooked on medium-high heat for 10-20 mins, Dum process is done with Kanal made with chakiri (outer skin of coconut burned and in red color like charcoal) is lined on the top and cooked on low flame for 10-15 mins.
Those who don’t have access to Kanal-charcoal.After 10 mins, when one side is done, open the lid and just flip the fish, cover and cook for another 10 mins. Make sure not to break the fish, so gently flip the fish.
Traditional recipe doesn't call for flipping the fish. It's gets cooked perfectly on Dum with charcoal. Here it takes little time to cook because we have not used water.
After flipping the fish, cover it with banana leaf, cover and cook it for another 10 mins. So totally we need 30 mins of cooking time.
Tasty Mathi-Chala Thappu Vechathu-Sardine Dry Curry is ready. Serve hot with Rice or Steamed Tapioca/Kappa Puzhukku