Melt the butter in a saucepan. Add the lima beans and scallions and cook until the beans are tender.

Empty the mixture into the container of an electric blender. Add the salt, pepper, marjoram and parsley; cover and blend on high speed for twenty seconds.

Remove the blender cover and, with the motor on, gradually add the cream or milk. Turn off the motor as soon as all the cream is added.

Pour the mixture into a saucepan and add the stock. Heat over simmering water. Garnish with chopped chives or parsley.