Grate the corn off six ears. Cover this with cold water and bring to a boil cooking about 0.75 hour. Cut the corn from the other six ears and combine with the grated corn. Mash the egg yolks and mix with the flour and butter. Slowly add the water in which the cobs have cooked and mix well. Add corn and the parsley and, if mixture is too thick, add enough milk to make of right consistency. Bring to a boil and cook for 5 minutes.