Cottage Cheese Potatoes

Place potatoes in a large pot of water and boil until tender when pierced with a fork.
Preheat oven to 350 degrees F (175 degrees C). Butter a 9x3 inch casserole dish.
In a large mixing bowl, combine potatoes, onion, cottage cheese, and sour cream. Transfer mixture to the prepared casserole dish. Top with Cheddar cheese.
Bake at 350 degrees F (175 degrees C) for 30 to 40 minutes.