London cure salmon with avocado puree and horseradish 'snow'

Ingredients

For the horseradish snow
400g/14¼oz fresh horseradish
275ml/9¾fl oz milk
275 ml/9¾fl oz double cream
37g/1¼oz cornflour
1.5 litre/2 pints 13fl oz buttermilk
salt and freshly ground black pepper
For the salmon
4 x 75g/2½oz pieces London cure smoked salmon
olive oil, for drizzling and frying
For the potatoes
3 Pink Fir potatoes
salt and freshly ground black pepper
1 bay leaf
3 sprigs fresh thyme
For the avocado purée
6 ripe avocadoes, peeled, stone removed
200g/7oz crème fraîche
3 limes, juice only
salt and freshly ground black pepper
To serve
1 tbsp olive oil
salt and freshly ground black pepper
½ loaf good quality rye bread, frozen, very thinly sliced and toasted
1 punnet baby watercress

Method

1. For the horseradish snow, feed the fresh horseradish into a vegetable juicer and place the juice into a measuring jug. (You need 270ml/9½fl oz horseradish juice.)
2. Place the milk and cream into a pan over a low heat and stir. Add the cornflour and stir to dissolve and thicken the liquid.
3. Add the buttermilk and the horseradish juice and season, to taste, with salt and freshly ground black pepper. Remove from the heat and leave to cool in the bags. Once cool, pour into a deep-sided baking tray and transfer to the freezer. When the horseradish mixture has frozen, remove and break up in a bowl with a fork.
4. For the salmon, place the salmon into vacuum-pack bags with a drizzle of olive oil and seal. Place into a water bath at 40C/104F and cook for ten minutes, then leave to cool.
5. For the potatoes, thinly slice the pink fir potatoes lengthways. Place the potato slices, bay leaf and thyme into a pan of boiling salted water and cook for 4-5 minutes. Drain the potato slices and place onto a baking tray and set aside. Discard the thyme and bay leaf.
6. For the avocado purée, place the avocado flesh, cr`me fraîche and lime juice into a food processor and blend until smooth, Season, to taste, with salt and freshly ground black pepper, then pass through a sieve and spoon into a piping bag. Set aside.
7. To serve, remove the salmon from the vacuum bags. Place the salmon portions and a little olive oil into a frying pan over a low heat just to warm through.
8. Place the reserved cooked potato slices into a bowl, season, to taste, with salt and freshly ground black pepper and dress with olive oil.
9. Place a piece of warmed salmon onto each plate, top with the potato slices and the toasted rye bread and garnish with baby watercress leaves.
10. Pide a swirl of avocado purée around the edge of the plate. Add a spoonful of the horseradish snow and serve.