Add the cannellini beans, vegetable broth, onion, carrots, garlic, rosemary, oregano, and red pepper flakes to the slow cooker.
Season with salt and black pepper, then stir to combine the ingredients evenly.
Cover and cook on low for 6 hours or on high for 3 hours until the vegetables are soft.
Stir in the chopped kale during the last 30 minutes of cooking so it wilts but keeps some texture.
Taste and adjust salt and pepper if needed before serving.
Ladle the soup into bowls and top each serving with grated Parmesan cheese.