Trim fat from ham steak; coarsely chop ham. Reserve bone.
Cook ham in hot oil in a Dutch oven over medium-high heat, stirring often, 6 to 8 minutes or until browned. Add diced onion, and next 5 ingredients, and sauté 5 minutes or until onion is tender.
Stir in reserved ham bone, navy beans, and next 3 ingredients; add water to cover. Bring to a boil; cover, reduce heat to low, and cook, stirring occasionally, 45 minutes. Remove and discard bone before serving. Stir in spinach just before serving. Garnish, if desired.
I made this when I first saw the recipe in 2008. The first time I didn't have the ham-flavored soup base, so I used chicken soup base instead. It turned out wonderful with either ham or chicken soup base. Since all the beans are canned, it is the easiest bean soup I've ever made and it has the added bonus of providing plenty of leftovers that freeze very well.
This is delicious. I did not add the potatoes. My entire family loves this recipe. It's a definite keeper. My mom was skeptical and told me that is not how she made ham and beans but after she tried it she said it was very good too. I served with sweet corn bread.