Very nice recipe of Laura Vitale. Easy and simple to make. I honestly have to say that I've never ever heard of escarole. I had to look for some information.
Here is a link of Cookthink. And here an explanation of culinary arts. A link of wisegeek with some picture.
As I was looking for pictures I also saw this delish recipe with "scarole" I think the Italians use the short version.