1. Heat the oil in a large non-stick frying pan over a medium heat. Add the sliced onions and fry for 5 minutes, stirring regularly.
2. Mix Shemin’s Seafood Curry Paste with enough water so that it is the texture of cream, add to onions and fry on a gentle heat stirring constantly. If the sauce gets too dry add a little more water.
3. Add the chopped tomatoes, chilli, vinegar and a splash of water. Bring to simmer and cook for 5-6 minutes until the tomatoes have softened, stirring regularly.
4. Pour in the coconut milk, salt and sugar into the pan. Bring to a gentle simmer.
While the sauce is simmering cut the fish into chunks about 3cm – enough for 1 mouthful. If using monkfish, remove the membrane before cutting into chunks.
5. Stir the fish into the curry sauce and simmer for 3-5 minutes, until just cooked. Give the pan a little shake now and again. If stirring be careful not to break up the fish. Adjust the seasoning.
Serve with boiled rice