How to Make It
Layer sliced potatoes in a lightly greased 6-quart slow cooker; top with chopped onion.
Stir together chicken broth, salt, and pepper; pour over potatoes and onion. (Broth will not completely cover potatoes and onion.) Cover and cook on HIGH 3 to 5 hours or until potatoes are tender. Mash mixture with a potato masher; stir in half-and-half. Cover and cook on HIGH 20 more minutes or until mixture is thoroughly heated. If desired, use an immersion blender to smooth out lumps.
Ladle into bowls, and serve with desired toppings.