Place a large pan over a medium heat and add the oil. Add the onion, lower the heat slightly and cook gently until it has softened and become translucent (about 10-15 minutes). Finely chop the coriander stems, then – when the onion has had its time – add them to the pan, together with the prepared garlic and chilli, and the ginger. Cook for a couple of minutes, stirring all the while, then add the cumin and mustard seeds and the turmeric, and cook for a further minute or two until the spices smell fragrant. Now is probably a good time to cook the rice, according to the pack instructions.

Pour the coconut milk into the pan and increase the heat to bring the pan up to the boil, then reduce the heat and simmer for 5 minutes, stirring gently, until the sauce has reduced and thickened slightly. Put the prepared Pollock into the pan, season with a good pinch of salt and some black pepper, then cover the pan and simmer for another 5 minutes until the fish is cooked through (as a rough guide, the fish is ready when it has become opaque and is easy to flake with a fork). Stir the chopped coriander leaves into the curry, then serve straight away with the cooked rice, and some cooling plain yoghurt or your favourite chutneys alongside.