How to Make It
Heat the oil in a pot. Add the onion and garlic and cook over moderate heat, stirring occasionally, until softened, about 10 minutes. Add the escarole and rosemary and cook until the escarole is wilted, 3 minutes. Add the stock, beans and tuna and bring to a boil. Simmer over low heat for 5 minutes. Season with salt and pepper. Serve the soup with shredded Parmesan and crusty bread.