Mix the potatoes, shallots and cheese in a large mixing bowl until well mixed. Season with salt and pepper. Fold in the sour cream one cup at a time.
Oil a large baking dish (13 X 9 or larger pan will do) very well. Place the potato mixture in the pan and sprinkle top with the reserved cheddar cheese. Bake in a 350 oven for 25 minutes until hot and lightly browned.