In a large pot, heat 2 tablespoons olive oil over medium heat. Add sausage and brown, stirring occasionally to break into smaller pieces, approximately 10 minutes.
Add onion, carrots, potato, and bay leaves. Season generously with kosher salt and cook until vegetables begin to soften, stirring occasionally, approximately 10 minutes.
Add garlic and beans, and cook for another 2-3 minutes. Add kale, and cook until it becomes slightly wilted. Add chicken stock, season with salt and pepper, and cover with lid.
Bring soup to a boil, then reduce heat and keep at a simmer for about 45 minutes, although a bit longer is completely fine. The soup will thicken as the potatoes begin to release their starch into the soup.
*the soup tastes best the second day. If time allows, cool soup completely, and refrigerate it for the following day. Reheat before serving.
**works well for vegetarian, just omit the sausage and use a vegetable stock (be careful not to have a vegetable stock that contains too much carrot—will make the soup strangely sweet. I often use bullion cubes for vegetable stock.
***I like to use dried beans when preparing a large quantity of this soup. You need to start a day in advance so you can soak the beans and cook them.