Rhubarb Upside-Down Cake
["5 c. fresh or frozen rhubarb (1/2-inch pieces), thawed and drained", "1 (6 oz.) pkg. strawberry gelatin", "1/2 c. sugar", "2 c. miniature marshmallows", "1 (18 1/4 oz.) pkg. white or yellow cake mix"]
["Place rhubarb in a greased 13 x 9 x 2-inch baking pan. Sprinkle with the gelatin, sugar and marshmallows. Prepare cake mix according to package directions. Pour batter over marshmallows. Bake at 350\u00b0 for 50 to 55 minutes or until a toothpick inserted near the center comes out clean. Cool for 10 minutes. Invert cake onto a serving platter. Serve with whipped topping, if desired. Yield: 12 to 16 servings."]
["frozen rhubarb", "strawberry gelatin", "sugar", "marshmallows", "white"]