Escarole and Rice Soup

Adapted from Marcella Hazan 1 head escarole (3/4-1 lb) 2 TBL finely chopped yellow onion ¼ cup butter Salt 3 ½ homemade meat broth or 1 cup canned chicken soup mixed with 2 ½ cups water ½ cup rice preferably Arborio 3 TBL fresh grated parmesan   Detach escarole...