Start by heating a generous amount of extra virgin olive oil in a large pot over medium heat. Add the chopped onion, garlic, carrots, celery, and leek. Sauté them until they become soft and fragrant.
Once the vegetables are cooked, add the cavolo nero (Tuscan kale) and sauté for a few more minutes until it wilts slightly.
Next, add the cannellini beans and tomatoes to the pot. Stir everything together and let it cook for a few minutes, allowing the flavors to meld together.
Pour in the vegetable broth, ensuring that it covers all the ingredients. Bring the soup to a boil, then reduce the heat to a simmer. Let it cook for about 30 minutes, allowing the flavors to develop.
While the soup is simmering, take your stale bread and tear it into small pieces. Add the bread to the pot, stirring gently to incorporate it into the soup. The bread will absorb the flavors and thicken the soup.
Continue simmering the soup for another 15-20 minutes, stirring occasionally to prevent sticking. The soup should have a thick, stew-like consistency.
Season the soup with salt, pepper, and your choice of fresh herbs. Taste and adjust the seasoning according to your preference.
Remove the pot from the heat and let the soup rest for a few minutes before serving. This will allow the flavors to further develop and meld together.
Ladle the Tuscan Soup into bowls and drizzle each serving with a generous amount of extra virgin olive oil. You can also sprinkle some freshly grated Parmesan cheese on top for added richness.
Serve the soup hot and enjoy the comforting flavors of Tuscany in every spoonful.