For the cream of leek soup, clean and wash the leeks and cut into thin strips. Set aside a few strips as garnish for the soup.
Heat oil in a saucepan and fry the leeks a little in fat. Pour in water. Cook the leeks until soft. Puree with a blender and thicken with flour and creme fraiche.
Finally, season with vegeta, salt and pepper. Serve the cream of leek soup on plates and garnish with leek rings.