Place the beans in a large bowl with water, using your hand swirl the beans around to rinse them and discard any small stones or beans that look brown. Drain the beans in a colander, rinse and refill the bowl with beans and a generous amount of water (at least 2-3 inches above the beans) and let soak overnight or for at least 6 hours.
Drain the beans, rinse well and place in a Dutch oven or large pot. Add 7 cups water, 5 of the sage leaves, the tomato halves and bring to a boil uncovered over med-high heat. Reduce heat to a gentle simmer and cook uncovered until the beans are tender 1 1/2 - 2 hours, be sure to test for doneness. Drain and reserve the beans, discard the sage and tomato halves.
In a large sauce pan, heat oil over medium heat. Add garlic, 5 remaining sage leaves, onions, carrots, celery, red pepper flakes and saute for 8-10 minutes until the ingredients are soft and translucent. Stir in the cooked beans and crushed tomatoes. Add the salt, pepper and the chicken stock. Stir together and simmer gently, when all ingredients are combined and warmed, stir in the mascarpone cheese until melted and evenly folded into the tomato and bean mixture. Add salt and pepper to taste. Cover saucepan to keep warm and turn off heat until ready to serve.
Cook the sausage by braising or grilling. Once the sausages are cooked, transfer them to a cutting board and cut into halves or thirds. Transfer the warm beans to individual bowls and arrange sausage pieces on top. Garnish with a sprig of fresh sage.
* To Serve 4-5, prepare the same recipe with 1 package of Johnsonville Italian sausage.
* mascarpone cheese is a mild flavored, creamy Italian cheese and can be found in the specialty cheese section of most grocery stores.