Step 1: Prepare the beans. Sort through 1 pound of dried Great Northern or cannellini beans, discarding any debris. Rinse thoroughly. Soak the beans overnight in a large bowl covered with several inches of cold water, or use the quick-soak method (boil beans for 10 minutes, then let sit for 1 hour, covered). Drain and rinse the soaked beans before proceeding.
Step 2: Render the ham hock (if using). In a large heavy-bottomed pot or Dutch oven, place the smoked ham hock. Add enough water or chicken broth to cover the ham hock by about an inch. Bring to a boil, then reduce heat and simmer gently for about 30-45 minutes, or until the meat is tender enough to shred. Remove the ham hock, let it cool slightly, then shred the meat from the bone. Discard skin and bone. Reserve the broth.
Step 3: Sauté the aromatics. If using bacon instead of ham hock, dice 4 slices of thick-cut bacon and render it in the pot until crispy. Remove the bacon bits, leaving about 2 tablespoons of fat. Add 1 tablespoon of olive oil to the pot (if needed). Add 1 large chopped yellow onion, 2 stalks of chopped celery, and 2 chopped carrots. Sauté over medium heat for 8-10 minutes, until softened and lightly caramelized.
Step 4: Build the flavor base. Add 4 cloves of minced garlic to the pot and cook for another minute until fragrant. Stir in 1 teaspoon dried thyme, 1/2 teaspoon dried rosemary, 1/4 teaspoon smoked paprika, and a pinch of red pepper flakes (optional, for a little heat). Cook for 30 seconds, stirring constantly, until aromatic.
Step 5: Combine and simmer. Add the drained, rinsed beans to the pot. Pour in 6 cups of low-sodium chicken broth (or the reserved ham hock broth) and 2 cups of water (or more broth if not using ham hock broth). Add the shredded ham meat (if using). Bring the mixture to a boil, then reduce heat to low, cover, and simmer for 1.5 to 2 hours, or until the beans are very tender. Stir occasionally to prevent sticking.
Step 6: Adjust seasoning and consistency. Once the beans are tender, taste the soup and season generously with salt and freshly ground black pepper. Remember that smoked ham hocks can be salty, so add salt gradually. If you prefer a thicker soup, you can mash some of the beans against the side of the pot with a spoon or an immersion blender to thicken it slightly. For a creamier texture, you can blend about 1-2 cups of the soup, then stir it back in.
Step 7: Final touches and serve. Stir in 2 tablespoons of fresh chopped parsley or cilantro just before serving for a burst of freshness. Ladle hot soup into bowls and serve with your favorite toppings.