Surprise Cake
["1 box yellow or white cake mix", "miniature marshmallows", "1 c. walnuts", "brown sugar"]
["Mix cake mix as on box; put in cake pan.", "Put brown sugar over top and sprinkle walnuts over that.", "Put miniature marshmallows evenly over top.", "Bake at 350\u00b0 until golden brown.", "Makes its own frosting."]
["marshmallows", "walnuts", "brown sugar"]