Wash sweet potatoes and boil until tender in their jackets.

Remove peelings and mash thoroughly.

Mix butter in with potatoes

Separate 2 eggs and beat egg whites until stiff.

Mix egg yolks in with mashed potatoes.

Add in the following ingredients to the potatoes and mix thoroughly: brown sugar, sugar, allspice, cinnamon, vanilla and salt.

Fold in stiff egg whites to mixture and mix thoroughly.

Pour potato mixture into baking dish and top with marshmallows.

Bake at 350°F until marshmallows are brown.