2 1/4 potatoes, peeled and cubed
1 1/2 oz. cream cheese
1/4 c sour cream
1/2 tsp chopped onion
1/4 tsp salt
1/8 tsp ground black pepper
1 1/2 tsp butter
1. Bring a large pot of salted water to a boil. Drop in potatoes, and cook until tender but still firm, about 15 minutes.
2. Transfer potatoes to a large bowl, and mash until smooth. Mix in the cream cheese, sour cream, diced onions, salt, pepper, and butter. Cover, and refrigerate 8 hours, or overnight.
3. Preheat oven to 350 degrees F. Lightly grease a medium baking dish.
4. Spread potato mixture into the prepared baking dish, and bake in the preheated oven about 30 minutes.