First, make the court bouillon. Put all its ingredients together in a medium pan. Cover with 2 litres water, bring to the boil and leave to simmer for 20 minutes. Strain into a deep sauté pan in which the trout will fit, side by side. Bring back to the boil, slide in the trout, making sure they are covered by the liquid (add a little boiling water from the kettle if necessary), and leave over the heat for 1 minute. Remove the pan from the heat and leave the fish to poach gently in the hot liquid for 10 minutes.

Meanwhile, put the potatoes into a saucepan of water, bring to the boil and cook for about 12 minutes or until tender. Drain well and cut the potatoes lengthways into quarters.

Lift the trout out of the poaching liquor and leave to cool for a few minutes. Remove the skin from 1 side of each fish, run a knife down the length of the fish between the 2 fillets and carefully ease them away from the bones. Turn the fish over and repeat on the other side. Break the flesh into bite-size pieces.

Make the dressing. Mix together the horseradish sauce, mustard and white wine vinegar in a small bowl. Gradually whisk in the oil to make a thick, creamy dressing. Stir in the shallot and salt and pepper to taste.

Toss the salad leaves in 2 tablespoons of the dressing and arrange in the centre of 6 plates with the potato wedges, beetroot wedges and the trout. Drizzle the remaining dressing over each salad to serve.