Wash the potatoes, bring to the boil covered with water and cook for about 20 minutes. Drain potatoes, rinse and peel. Bring the stock to the boil, pour over the potatoes and leave to stand for 30 minutes. Cut beetroot into slices. Add oil and vinegar to the potatoes. Season to taste with salt, pepper and sugar.
Add silver onions, capers and beetroot. Wash the chives and cut into small rolls and add to the potato salad. Arrange potato salad on a plate. Arrange trout filets on top. Garnish with chive flowers