Start to colour the small shallots in pain with oil and season a high heat. Colour the cepes in oil, remove from the heat and add butter. Colour the fish in a non-stick pan, skin side down then put the fish in a hot oven - 180c - for 3-4 minutes.
Put the cepes back on the heat and add the chopped shallot and the chanterelles. Once the small shallots have coloured add some butter and a little water. Add some butter to the mushrooms, season and at the last minute add the chopped parsley. In a hot pan add the spinach, crushed garlic and season and a small amount of water. Cover with a lid for 30 seconds. Remove the fish from the oven and rest. Drain the spinach. Place the spinach in the bottom of a large bowl, then the fricassee of mushrooms and shallots around the edge, adding a liquor from the fricassee to the plate. Top with the John Dory.