2 cans cannellini beans--drained
1 large bunch cavelo nero, kale, swiss chard, or other dark leafy green--chopped
3 stems fresh italian parsley--chopped
3 garlic cloves--peeled and chopped
4-5 celery stalks-chopped
3 carrots--chopped
1 onion--chopped
1 large can diced tomatoes
1 loaf (approx) stale ciabatta or other hearty bread, crusts removed--sliced or torn
olive oil
chicken or vegetable broth
parmesan cheese

In a large stockpot, fry the onion, celery, carrot, garlic and parsley in about 3 Tbs olive oil on low for about 30 minutes.  Add the tomatoes, cavelo nero (or other leafy green), the beans and enough broth to cover. Simmer for an additional 50-60 minutes. 
The bread and broth are used to manage thickness of the soup.  I would start with 1/2 the bread and add more broth and let it sit on low heat for a bit, allowing the bread to break down.  Add more bread or broth to achieve the consistency you enjoy.  Season with salt and pepper.  When serving, top with some parmesan cheese and a glug or two of good olive oil.