Peel and finely chop the onion and garlic. Sauté in a little oil over a low heat until the onion is soft. Add a pinch of ground cumin and ground turmeric, and cook for a few minutes more. Add the tin of chopped tomatoes and simmer for five minutes until it has cooked down and thickened.
Meanwhile, cut the white fish fillet into small cubes, checking carefully for bones. Add the fish to the pan, stir and simmer for five minutes or until it's cooked through. Flake the fish and serve over boiled rice.
Cook's tip: for young babies, mash or purée the mixture or serve with a spoonful of rice for babies who are eating lumps.