1. Wash mackerel. slice the fish and keep it aside.
2. Heat the oil in a deep pan put cardamom, clove and cinnamon.
3. Saute garlic, ginger, curry leaves one by one until raw smell goes off.
4. Fry onion till golden brown. Then add tomatoes.
5. Once tomatoes are soft . Add red chilli paste.
6. In 2 mints throw in turmeric powder, cumin powder, coriander powder.
7. Keep stirring it until the paste changes in color. (5 to 7 minutes)
8. When its done you can see oil around wok and thats when its perfectly fried.
9. Now pour 2 cups of water to it, or as much thick gravy you want (as required).
10. Then add green chilly, vinegar, tamarind water and allow it to boil till oil floats.
11. Add salt as per taste.
12. Once the gravy comes to boil, start dropping the fish pieces and allow to boil for 15 minutes.
13. Switch off the flame.
14. Garnish with curry leaves.