Step 1

To make the cep purée, peel the defrosted mushrooms. Place the trimmings in a saucepan, cover with a layer of ice cubes and place on a medium heat. Bring to the boil and strain over a bowl containing the dried ceps. Return the dried ceps and stock to the pan, bring to a simmer and reduce the liquid by half. Strain again and set aside

Step 2

To finish the purée, heat a dash of olive oil in a saucepan, add the shallots and thyme and cook until soft with no colour. Roughly chop the cleaned frozen mushrooms and add to the pan. Cook until all the moisture has come out of the mushrooms, add the wine and reduce until there is roughly 50ml left in the pan

Step 3

Remove the thyme and add the contents of the pan to a blender with the butter and half of the mushroom stock. Blitz until smooth, adjusting the texture with more stock if needed. Season to taste, transfer to a saucepan and set aside

Step 4

For the mash, place the potatoes into a large pan and cover with water. Add a pinch of salt, bring to the boil and cook for 10–15 minutes, until tender

Step 5

To finish the mash, drain well and return the potatoes to the dry pan for a few seconds to steam and dry off a little. Mash the potato using a masher or ricer and add the olive oil. Beat until smooth and combined, seasoning generously with salt and pepper

Step 6

To cook the ceps, heat the oil in a frying pan on a medium heat. Once hot, add the mushrooms cut-side down and cook until golden. Turn the mushrooms, add the thyme and butter and allow to foam and sauté the mushrooms to coat in the fat. Add salt and white pepper to taste and keep warm

Step 7

Gently reheat the cep purée while you cook the fish. Heat a dash of olive oil in a large, flat pan and add the fish, skin-side down. Cook gently until half-cooked, then turn the fish over and remove the pan from the stove. The fish will cook through in the residual heat

Step 8

To serve, add a scoop of the olive oil mash to each plate. Place the John Dory on top and spoon the cep purée generously over the fish. Scatter over the ceps, season with salt and garnish with herbs. Serve immediately