Pre-heat an oven to 180*
Heat a frying pan, add the oil, season the fish with a little salt and pepper, cook the fish skin side down for 2 minutes and then put into the oven to cook for around 5 minutes.
Start the potatoes in cold water and bring to the boil, reduce to a simmer.
Cook the potatoes until tender, then drain and allow to steam for a couple of minutes.
Pick the leaves from the parsley and together with the rest of the herbs and finely slice.
Add the herbs, butter and seasoning to the potatoes and mash together.
Top and tail the green beans and cook for 3 minutes in boiling salted water, drain and toss with the butter and seasoning. Retain the water for blanching the watercress
Peel and dice the shallot and garlic
Melt the butter in a pan till its nut brown, add the shallots and garlic and cook for 2 minutes, add the cream and bring to the boil, reduce the heat and simmer for 2 minutes.
Blanch the watercress in boiling water for 30 seconds, refresh in cold water for the same and then squeeze dry, remove and discard any tough stalks before roughly chopping.
Put the watercress into a blender, add some of the cream and blend, adding more liquid to get the right consistency.
Plate the dish by making a pool of puree, place a mousse ring into the center, fill with the potato, top with green beans and then the salmon.
«If you want to make another meal out of this dish make some extra potatoes and puree, blend together to make a great soup»