Sweet Potato Soufflé

Boil 4 or 5 sweet potatoes, peel, and run through potato ricer. While hot, add 2 tablespoons butter, 2 tablespoons cream, 1 tablespoon sugar, pinch of salt, 1 well beaten egg, 1 cup chopped raisins, and a few nuts, if desired. Pour into baking dish, cover with marshmallows and brown.