Peel and chop the potatoes, then layer them in the slow cooker.
Add the diced onion, ham, cream of chicken soup, chicken broth, water, minced garlic, and black pepper on top.
Set the slow cooker to low heat and let it cook for 6 to 8 hours, or choose high heat and cook for 3 to 4 hours, until the potatoes are soft.
About 60 minutes before serving, mix the shredded cheese with the flour and milk in a separate bowl.
Pour this cheese mixture into the slow cooker and stir well, then cover and continue cooking.
Once fully cooked, dish out the soup and finish with the remaining cheese, crumbled bacon, and optional green onions as garnish. Serve hot and enjoy!