With an electric mixer, beat yams, pineapple, and cinnamon until smooth. Pour into a greased casserole pan.
Preheat oven to 350 degrees F. Combine the remaining ingredients and sprinkle on top. Bake 20 minutes or until marshmallows are golden brown. Serve warm.
A viewer or guest of the show, who may not be a professional cook, provided this recipe. It has not been tested for home use.