Preheat oven to cake mix box directions and spray a 13x9-inch baking dish with cooking spray. Beat cake mix, soda and egg whites 2 minutes; pour into prepared pan.
Decrease cooking time on box by 5 minutes. Bake until a toothpick inserted in the middle of cake comes out clean.
Cool the cake for 15 minutes then use a fork or toothpick to poke holes all over cake about ½-inch apart.
Mix together Jell-O and boiling water until the powder is completely dissolved, then stir in cold water. Pour over poked cake. Refrigerate until cooled completely.
Once cake is cooled, combine milk and instant pudding. Beat 2-3 minutes until combined and thickened. Fold in about half a container of lite frozen whipped topping until smooth and spread over cake.
Garnish with maraschino cherries, if desired. Keep refrigerated.