Preheat oven to 350°F. Grease 13x9-inch baking dish.
Preheat oven to 400°F. Grease gratin dish or 11x7-inch baking dish.
Preheat oven to 450°F.
Place potatoes and water in large slow cooker. Dot with butter and sprinkle with salt. Cover and cook on HIGH 4 to 5 hours or until potatoes are very tender.