Marrow beans

Marrow beans are plump white beans with a creamy texture.  These beans were popular in the U.S. in the 1850's as a baking bean. They have the flavor of bacon and work well pureed for soup.

Where To Buy Marrow Beans

You may not find these at your local grocery store but look for them in specialty food shops.  The can be readily had via several sources on Amazon.com: Marrow Beans

If you don't have marrow beans you can substitute great northern beans.