In a pot, heat the oil on medium-high, about 3 minutes
Add in the chopped onions, minced garlic and whole cumin seeds. Allow to brown, stirring often.
Add in the chopped tomatoes and about 1/2 a cup of water. Bring to a boil, then simmer on medium-low heat, stirring occasionally. We are aiming to get the gravy to a thick, mush consistency, slightly thicker than the picture of the gravy above.
Once the gravy has thickened and there isn’t a lot of water left, add in the fish chunks. Bring to a boil and simmer for 10 minutes. The fish will release a lot of its own water, therefore there should be no need to add any extra water.
Begin to stir the curry and break the fish chunks with your spoon. This should not take a lot of effort as the fish will have softened considerably by now. Continue breaking until the fish resembles keema (mince)
Keep cooking the curry on medium/low heat till the water evaporates. The curry is complete when there is little to no soupy water.
Serve with rice or chapattis and garnish with chopped fresh coriander and green chilli (optional).