Add unsalted butter and diced onion to a large pot. Cook over medium heat until the onions are softened, then add minced garlic and cook for 1 minute.

Add chopped cabbage and cook until it softens and wilts.

Add peeled and chopped russet potatoes, vegetable broth, salt, and black pepper. Bring to a simmer and cook for 20 minutes or until the potatoes are tender.

Use an immersion blender to mostly blend the soup but still leave some potato chunks for added texture. The soup will be thick.

Stir in half and half and chopped kale leaves. Heat the soup until the kale slightly wilts. Serve the soup with sliced green onion and chopped cooked bacon for garnish.