Clean and make slits lengthwise on the fish. Marinade the fish with the marinade ingredients listed and set aside until you prep the other ingredients (5 minutes)
In a pan, heat some coconut oil and lightly fry the fish for a couple of minutes only on each side. Do not fry the fish completely, it will cook more later. Just get it seared lightly on each side. Set it aside
In the same pan, heat some more oil and add the onions, ginger, garlic and curry leaves. fry until onions have softened.
Add the spice powders and salt and saute this for another minute. Do this on a medium flame to prevent the spices from burning
Still on a low-medium flame, add coconut milk and stir until just combined
Switch off the flame and add the shallots, stir to combine with the masala. The shallots will cook slightly in the next stage and retain it's crunch, more yumm.
Wilt the banana leaves by sliding them over a flame until they become softer and more pliable
To layer. Place a layer of the onion masala on the banana leaf and place the fried fish on top. Add another layer of masala on top
Wrap the banana leaf around the fish making a parcel, use a string to keep it closed
Place the parcel on a lightly oiled pan on a low flame. Cover with a lid to allow it to steam gently and cook on one side only for 5 minutes
To serve, unwrap the fish from the banana leaf (you can keep it on the leaf) and drizzle some coconut oil over the top. Serve warm with porotta, chappati or even plain steamed rice.