Slow Cooker Scalloped Potatoes

8 C sliced potatoes or 4 lbs mini potatoes
1 thinly sliced large onion
2 cans cream of mushroom soup (or 1 can and 1 can cream of celery)
1 can milk or light sour cream (using the empty soup can as a measure)
pepper and paprika

Peel potatoes, if using regular potatoes. No need to peel if using mini potatoes. Slice and place half into buttered slow cooker/crock pot. Top with thinly sliced onion. Mix soup and milk in shaker container and pour half of it over onions. Repeat with potatoes and the rest of the soup mix. Sprinkle with pepper and paprika. Cook on high heat for one hour, then turn down to medium and cook for another four hours or until potatoes are soft. You can slow this down (seven hours) by cooking on low/medium heat the whole time or speed it up by cooking on high heat the whole time. Once they are done, keep warm on the lowest setting. Serves 10 to 12.