In a large soup pot, heat the olive oil. Add the onions, green bell peppers, celery and garlic to the oil and cook over medium heat until the onions are translucent.

Add the beans, salt, bay leaf, cumin, oregano, and lemon juice and stir well.

Cover and simmer for 30 minutes, stirring occasionally to prevent sticking.

Add the vegetable broth and stir. When the broth begins to boil, turn the heat down and simmer for another 10 minutes.

Remove one cup of soup and pulse in a food processor 4-5 times. Return mixture to soup, stir and reheat to serving temperature.

If desired, serve with shredded cheese.