Poached salmon with water crest mayonnaise

Ingredients

• 1 carrot, chopped
• 2 celery stalks, chopped
• 1 onion, sliced
• 1 small fennel bulb, sliced
• 2 flat-leaf parsley stalks, bruised, plus 2 tbs chopped leaves
• 400ml white wine
• Pared zest of 1 lemon
• 1 tsp whole black peppercorns
• 1kg piece skinless salmon fillet
• 1kg chat potatoes, peeled
• 20g unsalted butter

Watercress mayonnaise (makes 350g)

• 3 egg yolks
• 1 tbs Dijon mustard
• 1/2 tsp lemon zest, plus 1 tbs lemon juice
• 1 cup (250ml) extra virgin olive oil
• 2 cups (50g) picked watercress leaves, finely chopped, plus sprigs to serve

Method

1. Place carrot, celery, onion, fennel, parsley stalks, wine, lemon zest and peppercorns in a large saucepan or stockpot and cover with 3L water. Simmer over medium heat for 25 minutes. Line a sieve with muslin or a clean tea-towel, strain stock in a deep, wide pan, discarding solids.
2. Return stock to medium-low heat and bring to a gentle simmer. Add the salmon and poach for 10 minutes. Remove from heat, cover and leave the salmon to cool completely in the liquid to finish cooking.
3. Meanwhile, for the mayonnaise, place the egg yolks, mustard and lemon zest and juice in a food processor and whiz to combine. With the motor running, add oil in a slow steady stream until thickened.
4. Add the chopped watercress and 2 tablespoons warm water, then whiz to combine. Season, then chill until needed.
5. Place the potatoes in a large saucepan of cold, salted water. Bring to the boil over medium-high heat. Cook for 10 minutes or until tender. Drain, toss with parsley leaves and butter. Allow to cool slightly.
6. Carefully remove the salmon from the poaching liquid. Break the salmon into large pieces and arrange on a serving platter with the potatoes and lightly dressed watercress sprigs. Drizzle with the watercress mayonnaise, season with sea salt and freshly ground black pepper and serve.