2cups finely shredded lettuce, escarole, romaine, or spinach (see note below)
Salt and freshly ground black pepper to taste
Melt 3tablespoons of the butter in a saucepan and stir in the flour, using a wire whisk.
Add the chicken broth, stirring vigorously with the whisk. When the mixture is thickened and smooth continue cooking over low heat for 15 minutes.
Stir in the shredded greens and the cream and simmer for 5 minutes more. Season the soup to taste with salt and pepper and turn off the heat. Stir in the remaining butter and when it melts serve the soup immediately in hot cups or soup plates.