Drain the soaked beans and then cover them with water by about 2 inches in a large pot. Bring to a boil and remove from the heat. Let the beans stand, uncovered at room temperature for 1 hour. Drain and rinse beans in a colander.
Cook the sausage in a large saucepan over medium high heat. Use a wooden spoon to break up the meat a bit. Cook until no longer pink and lightly browned. Remove the meat with a slotted spoon and set aside.
Add the onions to the pot along with the garlic, thyme, pepper flakes and salt. Cook, stirring often, until beginning to soften, about 6 minutes.
Add the beans back to the pot along with the bay leaf, 6 cups of water, carrots, and parsnips. Bring to a boil, reduce the heat and simmer on low until the beans are cooked and veggies are tender. About 40-50 minutes.
Add the sausage back to the soup along with the kale and cook until warmed through. If the soup seems too thick, add more stock to thin as needed.
Serve with freshly grated parmesan cheese, salt and pepper.