Dissolve the butter in a saucepan, and place in it the onions and potatoes sliced; then add water, salt and flavourings, and boil for one hour. In the meantime prepare the kale by picking off all but the tender middle shoots, trim the stalks and throw the kale into salt and water; rinse well and see that it is all quite free from insects, and boil separately in salted water for ten minutes. When the soup has boiled an hour, thicken with the sago and continue stirring ten minutes, strain, return to the saucepan. Strain also the kale, place it on a chopping board and cut small; add it to the soup, boil up and serve.
Note. Any kind of greens may be treated in the above manner.