Step 1: Rinse the dried Great Northern beans thoroughly under cold water. Inspect for any small stones or debris and discard them. Place the rinsed beans in a large bowl and cover them with at least 3 inches of cold water. Let them soak overnight (8-12 hours) at room temperature. Alternatively, for a quick soak, bring beans and water to a boil, boil for 2 minutes, remove from heat, cover, and let stand for 1 hour.
Step 2: Drain and rinse the soaked beans. Set aside. In a large stockpot or Dutch oven, heat the olive oil over medium heat. Add the chopped onion, carrots, and celery. Sauté for 8-10 minutes, or until the vegetables are softened and the onion is translucent.
Step 3: Add the drained beans, ham bone, minced garlic, dried thyme, dried bay leaves, and black pepper to the pot. Pour in the chicken or vegetable broth, ensuring the ham bone and beans are mostly submerged. Add more water if needed to cover them adequately. Bring the mixture to a boil over high heat.
Step 4: Once boiling, reduce the heat to low, cover the pot, and let it simmer gently for 2-3 hours, or until the beans are tender. Stir occasionally.
Step 5: Carefully remove the ham bone and bay leaves from the pot. Allow the ham bone to cool slightly. Once cool enough to handle, shred any remaining meat from the bone and dice any larger pieces. Discard the bone and bay leaves.
Step 6: Stir the shredded ham back into the soup. Taste and adjust seasonings, adding salt to taste. Keep in mind that ham can be quite salty, so add judiciously. If the soup is too thick, add a little more broth or water. If it’s too thin, you can mash some of the beans against the side of the pot with the back of a spoon to thicken it slightly. Serve hot.