Into a glass bowl, place the monkfish and marinate with turmeric, some lime zest and lime juice, salt, pepper and 1 clove or two of garlic grated or made into a paste. Mix well to coat the fish and place in the fridge for 20 min to 2 hours to marinate. The longer the better.
Add the olive oil to a larger pan over medium-high heat and add the chopped onions, the seeds, cardamom, curry leaves, curry powder, the remaining garlic, ginger, chillies, salt and pepper. Cook, stirring, for about 10 minutes until the onion has softened and slightly coloured. I add some water as I do not like to fry it. I like the frying but just doesn't agree with us so I avoid it. It is healthier.
Stir in the roughly chopped tomatoes, tamarind paste and coconut milk; season, then bring to a boil. Simmer on low heat for approximately 10-15 minutes, uncovered stirring occasionally.
Add the monkfish and the marinade to the curry sauce and simmer over low heat for 6-8 minutes (depending on how chunky your fish is). Cook until the fish is cooked through and becomes opaque.
Remove the cardamom pods. Taste and season to perfection.
Serve on steamed basmati or jasmine rice. Scatter some chopped coriander leaves.