Marinate the cleaned fish cubes with the ingredients listed under "for marination". Keep aside for half an hour.
Shallow fry the fish pieces in a wide pan, till it's almost done.
Crush together the pearl onion, garlic with skin, and ginger.
Add turmeric powder, crushed red chilli flakes, crushed black pepper, coconut oil (1/2-1 tbsp) and curry leaves to the crushed pearl onion, ginger & garlic. Mix everything well with your fingertips.
Heat 1 tbsp coconut oil (use the same pan itself) and add the pearl onion and spice mixture. Cook for 4 – 5 mins or till the raw smell goes. Add a pinch of fenugreek powder. Add soaked kudampuli along with the pulp.
Add fried fish pieces and salt. Mix well. Cover and cook on low flame for 8-10 mins.
Add some more curry leaves and remove from fire.