Using whatever kind of white beans you like.
Sure, the recipe specifies northern or navy beans, but you could just as easily throw cannellini in there, too. From the cook’s perspective, while these vary in size (with cannellini being the largest and northern being the smallest), they have basically similar properties, and when you’re using them in a soup and appearance doesn’t much matter, you don’t have to worry about the differences too much.
From a box sold in East Moline, Illinois.
Bean Soup
2 lbs. Northern or Navy Beans (soaked overnight)
2 ham hocks
1/2 lb. ham chunks
3 small cans tomato juice
2 sticks celery, diced
2 carrots, grated
1 large Tablespoon beef bouillon
1 medium size onion, chopped
Salt and pepper to taste
Cook on low fire until beans are done.