If using bacon, fry with most of the scallion in medium pot. Set aside and drain. If you don't use bacon but do use scallion, cook the scallion in a little butter until soft and set aside. Add milk to the same pot and simmer fresh beans for 20 to 30 minutes, being careful not to boil the milk. If it does boil, skim the milk skin from the top and discard.
After 20 minutes, check beans to see if they are cooked. They shouldn't be mushy, but give a little when you bite into them. Add the bacon and scallions. Liberally salt and pepper. Serve hot with remainder of uncooked scallion for garnish.