Clean the radishes, put the green aside. Wash the radishes and chop them coarsely, except for 4 pieces. Clean or sort the radish greens, wash, shake dry and chop coarsely. Clean and wash spring onions and cut into rings. Peel, wash and chop the potatoes.
Bring the stock to the boil. Add potatoes and cook for about 15 minutes. After about 10 minutes add radishes, radish greens and spring onions and simmer. Wash mint, shake dry, pluck leaves from the stalks and cut into fine strips.
Puree the soup, stir in the cream, heat up and season with salt and pepper. Cut the remaining radishes into thin slices. Serve the soup and sprinkle with radish slices and mint. Sprinkle with oil.