If using dried beans, soak overnight, discard soaking water. Add beans to pot, cover with water by several inches. Add 1/2 onion (coarsly chopped), and 3-4 bay leaves. Simmer until soft (about 45 minutes). When done, drain in sink.
While beans are cooking, cut sausage in half lengthwise, then cut into half-moon slices. Heat 1 tsp olive oil in heavy Dutch oven, sauté sausage until browned, about 5 minutes. When done, remove to bowl.
Add chopped onion to pot, sauté for 2 minutes, adding more oil if necessary. After 2 minutes, add chopped garlic and sauté for another 2 minutes.
Add tomatoes and juice, dried oregano, dried marjoram, and chicken stock to pot with onions and garlic. Add sausage back to pot and cook at a low simmer about 30 minutes.
After 30 minutes, add drained beans and simmer 15 minutes more. (If the mixture seems too dry at this point, add a bit more chicken stock.).
Add chopped basil and balsamic vinegar and simmer 5 minutes more. Taste, and add salt and pepper as needed.
Serve hot with freshly grated parmasean (Romano works nicely as well).