Sear the sausage on all sides until browned in olive oil.
Add the garlic, sage, bay leaves, and rosemary (if using) and cook until fragrant, about 1-2 minutes.
Add the beans, tomato paste, and water. Use as much water as needed so that the beans are almost completely submerged.
Bring to a boil and then reduce to a simmer. Cover and cook for 15-20 minutes until reduced.
Serve with crusty bread, over polenta, or omit the sausage to serve as a side dish.
