SALMON:
1 whole salmon, weighing about 1 lb. 12oz filleted and pin-boned
FOR THE POACHING LIQUOR:
7fl oz white wine vinegar
1¾oz sugar
1 leek, sliced
1 onion, sliced
2 carrots, sliced
10 peppercorns
3 bay leaves
FOR THE SAUCE:
3½fl oz sour cream
2 tbsp mayonnaise
small bunch each of parsley, dill and chives, finely chopped
½ unwaxed lemon, zest and juice
pinch of caster sugar
TO GARNISH:
1 lemon, sliced
½ cucumber, sliced
Begin by making the sauce. Whisk together the sour cream, mayonnaise and herbs. There should be about 1 tablespoon of each chopped herb. Add the lemon zest and a squeeze of juice, then season to taste with a pinch of sugar, salt and pepper. Refrigerate until needed but serve at room temperature.
Bring all the ingredients for the poaching liquor to a simmer in a large pan along with 2¾ pints water and 2 tablespoons of sea salt. Simmer for 5 minutes then pour into a fish kettle or large high-sided oven tray set over a medium heat.
Carefully lower the salmon fillet into the liquid, ensuring it is completely covered (if not, add a little more water). Bring to barely a simmer and cook for 10–12 minutes until the fish is just cooked. Lift the fillet out of the poaching liquid and onto a plate, carefully peel off the skin and allow to cool completely.
Serve garnished with the lemon and cucumber slices and the room temperature sauce alongside.