Ribollita is an Italian tomato based bread soup. Technically, the soup is thickened by bread. I personally don't like that, so instead of cooking and soaking the bread in the soup, I make homemade croutons to go on top to add another level of texture. A few ingredients that make this recipe "just right," is the parmesan rind (omit for vegan), fresh herbs, homemade croutons and a squeeze of lemon.
Chop the onion, carrots and celery. Mince the garlic.
In a large pot, over medium heat, place 2 tbs of olive in it. Add the onion, carrots and celery. Season with a pinch of salt and fresh cracked black pepper. Let that cook for 5-7 minutes, until the vegetables have softened. Add the red pepper flakes (if using), dried / fresh rosemary and the garlic. Cook until the garlic is fragrant (1 minute).
Add the canned tomatoes, vegetable broth, thyme, bay leaf, parmesan rind (if using), and beans. Add a pinch of salt and a few grinds of fresh cracked black pepper. Stir.
Let the soup come to a boil, reduce to a very low simmer and place the cover on it. Simmer the soup for 30 minutes.
Meanwhile rinse the kale and chop if necessary
Make the homemade croutons. Cut the sourdough bread into 1 inch cubes. Drizzle 1 tbs of olive oil over the bread and season with a pinch of salt and a few grinds of fresh cracked black pepper. Toast in a toaster oven for 2-3 minutes or until toasted. (or conventional oven broil for 2 minutes but watch closely!).
Add the kale. Add a pinch of salt and a few grinds of fresh cracked black pepper. Let that simmer for 5 minutes, until the kale has wilted.
Remove the parmesan rind (if serving immediately, keep it in there to continue to add flavor, just remember to remove it before serving), bay leaf and thyme sprigs (if using fresh).
Serve the soup with some croutons a few shavings of freshly shaved parmesan cheese (if using), fresh basil (if available) and a squeeze of fresh lemon juice.