Step 1: If using dried beans, rinse them thoroughly under cold water. Place the beans in a large bowl and cover them with at least 2 inches of cold water. Let them soak overnight (8-12 hours). Alternatively, for a quick soak, bring beans and water to a boil, boil for 5 minutes, then remove from heat and let stand for 1 hour. Drain and rinse well.
Step 2: In a large Dutch oven or heavy-bottomed pot, 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. Stir frequently to prevent burning.
Step 3: Add the minced garlic, dried thyme, and dried rosemary to the pot. Cook for another 1-2 minutes until fragrant, being careful not to burn the garlic.
Step 4: Drain and rinse the soaked beans again. Add them to the pot along with the vegetable or chicken broth, diced tomatoes (undrained), and bay leaf.
Step 5: Bring the soup to a boil, then reduce the heat to low, cover, and simmer for 1 to 1.5 hours, or until the beans are tender. The cooking time can vary depending on the age and type of beans. Stir occasionally and add more broth or water if the soup becomes too thick.
Step 6: Once the beans are tender, remove the bay leaf. Using an immersion blender, carefully blend about 1/3 to 1/2 of the soup directly in the pot until it reaches your desired consistency. If you don't have an immersion blender, carefully transfer a few ladles of soup to a regular blender, blend, and return to the pot.
Step 7: Season the soup generously with salt and black pepper to taste. Start with a little and add more as needed. Stir in the fresh parsley.
Step 8: Ladle the hot soup into bowls. Garnish with a drizzle of olive oil, extra fresh parsley, or a sprinkle of Parmesan cheese, if desired. Serve immediately with crusty bread.