The beans(you may use great northern beans instead) make their own rich sauce as they slowly simmer in their own broth with onions, fruity olive oil, and sage.
For a simple, satisfying meal, serve with crusty sourdough bread and thin shavings of Parmesan cheese. Feel free to add in more veggies, like carrots, celery, etc. You may just need to add in a little more water near the end.
Adapted from Fields of Greens restaurant cookbook.