Pan-Fried White Fish with Mussels, Cider, Potatoes

First, put the potatoes in a large saucepan and place over a medium-high heat. When the pan reaches the boil, lower the heat and simmer for 8-10 minutes, or until the potatoes are tender. Drain the cooked potatoes, then put them back in their dry pan to keep warm and set aside. While the potatoes are cooking, take the mussels out of the fridge and rinse them gently, then leave them for a while so that they come up to room temperature. When they have reached room temperature, give any open mussels a light tap – live mussels will close at this point, so discard any that don’t close when you tap them. Set the mussels aside for the moment.

To make the garlic butter, put most of the chopped parsley leaves (reserve some to use as a garnish) into a food processor and crush in the garlic cloves, then blend to combine. Tip in the softened butter, the half-teaspoon of lemon zest and a good pinch of salt, and blend again until you have a well-blended, green-flecked garlic butter. Scrape the butter on to a dish and refrigerate while you make the rest of the recipe.

To make the stock, put a generous drizzle of oil into a large saucepan (one with a lid) and place over a medium heat. When the oil is hot, lower the heat slightly and add the prepared onion, celery and carrot and the bay leaf. Cook gently, stirring, until the vegetables have softened and the onion is translucent, then season well with salt and pepper, put the mussels into the pan and pour in the cider. Turn the heat back up to medium, then put the lid on the pan and cook for two minutes until all the mussel shells have opened. Take the pan off the heat and let it cool for a couple of minutes, then carefully pour the stock through a sieve into a large jug or bowl. Use a slotted spoon to lift the mussels into a clean dish (throw away any mussels that are still closed), then put a lid or clean tea towel over the dish to keep them warm. Tip the stock back into its cooking pan, then put the lid back on and set aside.

Next, place a frying pan over a medium heat and add a good-sized knob of butter (about a tablespoon). When the butter is melted and foaming, put the two whiting fillets into the pan, skin-side down. Fry for about 8 minutes – the thicker the piece of fish, the longer it will need – then carefully turn the fillets over and cook for 3-4 minutes on the other side, until the flesh is just cooked through. While the fish cooks, put the pan containing the stock back on a medium heat and bring it up to a steady simmer. Cook for about 5 minutes, or until slightly reduced, then dollop the garlic butter into the pan and whisk until it has all melted and been incorporated into the stock. Tip the cooked potatoes into the sauce and stir in the rest of the lemon zest, then add the mussels gently to the pan and lower the heat slightly. Cook for a few minutes, stirring occasionally, until the mussels are heated through, and check you are happy with the seasoning – it probably won’t need much salt, but you may wish to add a few turns of the pepper mill. Meanwhile, lift each cooked whiting fillet on to a serving plate. When the sauce is heated through, divided it between the two plates, spooning it over and around the fish. Scatter over the rest of the parsley, then serve.