Wash the potatoes and cook in plenty of boiling water for about 20 minutes. Rinse under cold water, drain and peel. Cut the potatoes into slices and marinate them in the hot broth.
Wash the mint, shake dry, pluck leaves from the stalks and cut into fine strips, except for something to garnish. Mix cream, vinegar and mint and season to taste with salt, pepper and sugar.
Clean and wash spring onions and cut into fine rings. Pluck the salmon into small pieces. Remove potatoes from the stock. Use the stock for other purposes. Mix sauce, potatoes, spring onions and salmon.
Serve and garnish with mint.