Chop onions and sauté in butter until light yellow. Peel and dice potatoes. Chop leek and carrots. Add with the potatoes. Fill up with soup and make and strain for 30 minutes. Beat flour with cream. Add together with marjoram and parsley.
Cook for 10 minutes on low heat. Season with salt, pepper and nutmeg (freshly grated).
Before serving, add a small dash of vinegar. Add toasted bread cubes to taste or place finely grated Emmental cheese in the soup plates and pour over the hot soup.