Place the diced onion, minced garlic, and diced carrots in the slow cooker.
Add the drained white beans, crushed tomatoes, vegetable broth, Italian seasoning, salt, and black pepper.
Stir gently to combine everything evenly.
Cover and cook on low for 6 to 7 hours until the carrots are soft.
Stir in the chopped kale during the final 30 minutes of cooking so it wilts but keeps some texture.