Heat 1 tablespoon of olive oil in a Dutch oven over medium heat. Add the sausages and cook, turning occasionally, until browned and cooked through, about 15-20 minutes. Transfer the sausages to a plate lined with paper towel to drain. Leave a couple of tablespoons of the fat in the pan and drain the rest. Alternatively, you can cook the sausages in the oven at 425 degrees F for 15-20 minutes, or until cooked through. Transfer the sausages to a plate lined with paper towel to drain, reserving a couple of tablespoons of the fat. Once the sausages have cooled, slice into rounds.

Heat the remaining 2 tablespoons of olive oil (with the reserved fat) in the Dutch oven over medium heat. Add the onion, carrots and celery and season with salt and pepper. Cook until the onion is translucent and carrots are tender, 5-8 minutes. Add the garlic and cook for another minute. Add the 6 cups of broth and bring to a boil. Then reduce the heat, and simmer the soup for about 8-10 minutes. Add the cooked sausage, beans, kale and fresh herbs and simmer for another 10 minutes. Remove the sprigs of fresh herbs. Season the soup to taste with salt and pepper. Add a splash of vinegar and serve.