I first encountered this amazing treatment with a large snapper in Mexico City. My friend knew it would blow me away and it did (I would also add that Contramar, the restaurant in which I ate this, is the finest fish restaurant I know of. It was the most memorable lunch of my life).
For the sake of ease, I recommend using just the fillets from the fish, as preparing it in the same way as the picture overleaf can be tricky. Or tell the fishmonger that you want the fish filleted with the head split but left on and the fillets connected at the belly. You will need a griddle plate (or large a flameproof frying pan or sturdy baking tray).
Start by making the red sauce. Make a small cross in the base of each tomato with a sharp knife and cut out the green core. Put the tomatoes in a mixing bowl and cover with just-boiled water. Leave for about 30 seconds, then lift out with a slotted spoon. The skins should easily slip off. Cut the tomatoes into quarters and put them in a food processor. If they are whole, finely chop the chipotle chillies â€“ you should end up with 2 good teaspoonfuls. Add this to the tomatoes along with the garlic cloves, oregano, cumin seeds, orange juice and sea salt. Blitz hard until all the ingredients are well blended and the sauce is almost smooth.
Heat a small frying pan and add the oil. When it is almost smoking, pour in the tomato and chipotle mixture and simmer furiously to reduce the liquid, evaporating most of the water out of the sauce. This should take 2â€“3 minutes. Shake the pan a few times to prevent the sauce from sticking. Remove from the heat and leave to cool.
To make the green sauce, cut the green tomatoes in half and put in a food processor. Peel the onion and roughly chop with the chile (seeds in). Wash the coriander to remove any dirt from the stalks and trim only the very ends. Put the leaves and stalks in the food processor with the tomatoes, onion, green chile, lime juice and salt. Blitz hard until the mixture is almost smooth â€“ you may need to remove the lid and push the sauce down with a rubber spatula a couple of times until the right consistency is reached. Turn out the sauce into a small bowl and stir in the oil.
Place a large, flameproof griddle pan, frying pan or sturdy baking tray over a high heat (make sure that it will fit not only the fish but also completely under your grill before you use it). Preheat the grill to its hottest setting. Take the fish fillets and wipe dry with kitchen paper. Rub with a little sunflower oil and season generously with sea salt. Put 1 of the fish fillets on a board, flesh-side uppermost, and spoon the red sauce generously all over, spreading to the sides with the back of the spoon. Lift carefully on to the griddle, skin-side down. Put the second fish fillet beside it, again skin-side down, and brush the flesh lightly with sunflower oil. Cook the fish for 4â€“5 minutes until the skin is very crisp.
Next, place the griddle under the grill, close to the heat source, and continue cooking for a further 4â€“5 minutes until the chipotle sauce begins to char in places. Remove from the heat, taking care because the griddle will be heavy and extremely hot. Lift the fillets on to a wooden board, placing them side by side. Spoon the green sauce over the bare fish fillet. Garnish with lime wedges and serve.