1 Peel the onions. Rinse and drain the peas. Rinse and trim the snow peas and cut diagonally into pieces.
Sauté the vegetables together in some butter. Season with salt and pepper, and pour in the wine and the stock.
2 Rinse the fish, cut into 4 pieces and season with salt and pepper. Place in the sauce, cover and leave to stew gently for about 10 minutes.
3 Rinse, trim and drain the watercress.
Arrange the salmon on plates and distribute the vegetables over it.
Allow the sauce to boil down a little and then season to taste.
Drizzle over the fish and the vegetables and serve garnished with watercress.