Rhubarb Upside-Down Cake
["5 c. cut up rhubarb", "1 c. sugar", "1 (3 oz.) pkg. sugarless strawberry Jell-O", "3 c. miniature marshmallows", "1 pkg. white cake mix"]
["Mix rhubarb, sugar and Jell-O and place in greased 9 x 13-inch pan. Cover with marshmallows. Mix cake according to directions on box and pour over rhubarb and marshmallows. Bake at 350\u00b0 for 50 minutes or until cake tests done with a toothpick. Serve warm or cold with a drop of Cool Whip."]
["rhubarb", "sugar", "sugarless strawberry", "marshmallows", "white cake mix"]