Sockeye Salmon Fillet with Country Garden Herb Sauce

Ingredients

• 1 Sockeye Salmon whole fillet
• 1/4 cup olive oil
• Finely grated zest and juice of 1 lemon
• 2 tablespoons butter
• 1 small onion, finely chopped
• 4oz dry white wine
• 1oz watercress, finely chopped
• 1 tablespoon chopped fresh chives
• 1 tablespoon chopped fresh marjoram, oregano, or parsley
• 1 cup crème fraiche
• Salt and pepper, to taste
• Fresh herbs for garnish