Wash mackerel, cut the head, fins and tail and clean the tummy. Refer to this video to know how to cut a mackerel.
Add slits on both sides of the mackerel bone starting from tail to head.
Marinate the mackerel by applying red chili powder, turmeric powder and salt and keep aside for 30 minutes. (Refer to ingredients in marination section)
In a small mixing bowl, add finely chopped onion, finely chopped coriander leaves, red chili powder, turmeric powder, salt, and tamarind paste and mix well. If the mixture becomes dry, add 2 tablespoon water and mix. The mixture should not be watery as we will stuff this inside the mackerel.
Stuff 2 tablespoon of the spicy onion mixture on both sides of the mackerel bone. If any extra stuffing remains, apply it on top of the mackerel.
In a mixing plate, mix rava(semolina), rice flour, red chili powder, turmeric powder, and salt.
Roll the stuffed mackerel in the spiced rava and rice flour by holding firmly to avoid the stuffing from oozing out. Coat the mackerel nicely in the spiced rava.
Spread 2 tablespoon oil in a tava or frying pan. Place the rava coated stuffed mackerel in the frying pan and fry for 10 minutes on low flame. Drizzle some oil on the top and turn to other side and fry further for 8 – 10 minutes on low flame.