Turbot roasted over celeriac, fennel and leeks

Ingredients

30g unsalted butter

100ml olive oil

2 leeks, finely sliced

2 fennel bulbs, halved and sliced

1 small celeriac, peeled, quartered and slice

Large bunch of thyme

1.5kg turbot

3 slices of lemon

Instructions

• Heat the oven to 200°C/fan oven 180°C/mark 6. Heat a large, heavy-bottomed casserole and melt a third each of the butter and oil, then add the leeks and a large pinch of salt. Fry on a medium to high heat, until they start to colour, then add a splash of water and continue to cook for 10 minutes or so until they soften but retain a bit of bite. Remove to a large bowl and set aside.
• Cook the fennel in the same way, and then the celeriac, making sure you scrape up all the caramelised sediment from the casserole at the end to add to the bowl. When all the vegetables are cooked, return the mixture to the casserole along with the thyme, and heat them together, gently folding them so they are well mixed; then season with salt and pepper.
• Choose a baking tray large enough to fit the whole fish with the braised vegetables underneath. Spread the vegetables in a layer, then lie the fish on top, tucking lemon slices into the cavity around the head. I don’t bother to season the skin of the fish as I end up removing it to serve anyway and instead offer flaked salt at the table.
• Roast the fish and vegetables for 25–30 minutes. The length of time will depend on the thickness of the fish, but a good way to check is to insert a skewer just below the head and through the fish. If the flesh is cooked, it will meet no resistance.
• Remove the fish to a serving plate and put the vegetables in a separate dish. I like to serve the whole fish and fillet it at the table, or allow everyone to serve themselves. A bowl of watercress dressed with lemon and oil or some boiled potatoes are all you will need as accompaniment.