Mackerel on Potatoes and Bay

A scrumptious way to cook mackerel from The River Cottage Fish Book, by Hugh Fearnley Whittingstall and Nick Fisher.

This is a fantastic and very simple one-dish meal. The juices from the fish mingle with the olive oil and lemon juice to make a delicious, aromatic emulsion that sauces the vegetables beautifully. 

Go for new potatoes if you can, but main-crop spuds are certainly usable too. Choose a waxy variety, such as Cara or Maris Peer, and parboil them for 5 minutes or so before you begin. 

Either way, keep all the veg nice and chunky – this should be a wonderfully rustic sort of dish. If you want a more child-friendly version, use fillets from larger fish instead of a whole fish.

Ingredients
(Serves 4)
Olive oil
1kg new potatoes, scrubbed and cut into rough chunks about 2cm thick
2 onions, thickly sliced
4 garlic cloves, very roughly chopped
2 lemons, halved and sliced into thickish pieces
4–6 bay leaves
2 sprigs of thyme
4 mackerel, gutted
Salt and freshly ground black pepper

Method
Pour enough olive oil into a large, shallow roasting dish just to cover the base. Use your fingers to spread the oil all over the dish. Combine the potatoes, onions, garlic and lemons, season with plenty of salt and pepper and spread them out in the dish. 

Tuck the bay leaves and thyme in amongst the vegetables so they won’t burn in the oven. Put the dish in an oven preheated to 180°C/gas mark 4 and bake for 30–45 minutes, until the spuds are lightly browned and just about tender, taking the dish from the oven every 10 minutes and turning the vegetables over in their oily juices.

Meanwhile, season the mackerel well with salt and pepper. When the potatoes are ready, lay the mackerel on top, pour on another good splash of olive oil and return to the oven. Turn it up to 200°C/gas mark 6 and bake for a further 15–20 minutes (10 minutes if you’re using fillets), until the mackerel is just cooked and the vegetables are beginning to catch and crisp up nicely. (If you like, you can take the fish out halfway through for a quick basting with the juices from the tin.) 

Serve straight away. The dish doesn’t really need any accompaniment but a green salad wouldn’t go amiss.