Prep the beansSoak dried cannellini beans overnight in plenty of water. Drain and rinse before using.
Cook the sausageIn a large pot or Dutch oven, heat 1 tbsp olive oil over medium heat. Add sausage, breaking it into bite-sized pieces, and cook until browned. Remove sausage and set aside.
Make the soffrittoIn the same pot, add remaining olive oil. Sauté onions, celery, and carrots until softened, about 5–7 minutes. Add garlic and cook 1 minute more.
Combine ingredientsReturn sausage to the pot. Add crushed tomatoes, soaked beans, broth, water, oregano, thyme, and red pepper flakes. Stir to combine.
SimmerBring soup to a boil, then reduce heat to low. Cover and simmer gently for 1 ½ to 2 hours, or until beans are tender. Stir occasionally and add more water or broth if needed to reach your desired consistency.
SeasonTaste and adjust salt and pepper as needed.
ServeLadle into bowls and garnish with chopped parsley and a drizzle of olive oil. Top with grated Parmigiano-Reggiano if desired.