Preheat oven to 400 degrees.
Wash and dry potatoes. Pierce skin before baking. Bake potatoes for about one hour, or until the inside of potatoes is cooked.
Cut potatoes lengthwise, Remove pulp and reserve in a mixing bowl. Break the pulp with a fork; season with salt and pepper, and mix in 4 ounces butter.
Lightly oil 2 small potato Anna molds or 8 4-inch round by 2-inch molds. Divide the potato mixture between molds to form two potato cakes.
Bake 15 to 20 minutes. Unmold on platter. Serve hot.