Heat the olive oil over medium heat in a pot large enough to accommodate a large pot of soup. Add the celery, leeks, onion, carrots, salt, and dried herbs. Sauté until the carrot is slightly softened, and the onions are starting to stick to the bottom of the pan. The mixture should be very fragrant.
Use a wooden spoon to form a well in the middle of the vegetables, revealing about 3 inches of the pot. Place the harissa on the pot surface and stir for 1 minute. It should start to become paste-like. Mix into the rest of the vegetables.
Add the cooked beans, 16 ounces of the broth, the tomatoes and the balsamic vinegar. Simmer for 10 minutes.
Using a submersible blender, whirl the soup around for about 1 minute to slightly puree. If you don't have one, just transfer one cup of the soup to a blender or food processor and purée. Stir it back into the soup in the pot.
Stir in the last eight ounces of broth, or more if desired. Add a little lemon juice, to taste, to sharpen the flavors.
Serve with grated Parmesan cheese and Rosemary Olive Oil