In a large pot, heat 2 Tbsp. olive oil over medium high heat. When the oil is hot, add the onion and sauté until the onions are soft, about 3 minutes. Add the beans, garlic, 4 cups chicken stock, bay leaves and one sprig of rosemary. Cook until the beans are tender, about 45 minutes. Remove the bay leaves and rosemary sprig.
Add the remaining 2 cups of chicken stock, kale, carrot, tomato and sausage. Continue cooking for 20 more minutes.
Meanwhile, finely chop the remaining rosemary and add it to the soup, along with salt and pepper to taste. Taste the soup and adjust seasonings as needed.
Serve with an extra grind of fresh ground pepper and a sprinkle of parmesan cheese if desired.