01 - Heat the olive oil in a large pot over medium heat. Add the onion and cook until softened, about 4 minutes.
02 - Stir in the garlic, carrots, and celery. Sauté for 5 minutes, until vegetables start to soften.
03 - Add the beans, vegetable broth, rosemary, bay leaf, salt, and pepper. Bring to a gentle boil.
04 - Reduce heat to low, cover, and simmer for 20 minutes, allowing flavors to meld.
05 - Remove and discard the bay leaf and rosemary sprigs.
06 - For a creamier texture, use an immersion blender to partially puree the soup, leaving some beans whole.
07 - Stir in lemon juice, taste, and adjust seasoning as needed.
08 - Serve hot, garnished with fresh parsley and accompanied by crusty bread if desired.