Preheat oven to 350 degrees F. Liberally grease a 13x9" baking pan with cooking spray and set aside. In a large bowl, beat together the cake mix, OJ, egg whites, orange zest, and applesauce together with a handheld electric mixer for about 2 minutes or until completely combined and smooth. Pour into the prepared baking dish.

Bake for approx. 25-30 minutes or until a toothpick inserted near the center of the cake comes out clean or with moist crumbs. Cool completely.

Poke holes over the entire cake using the handle of a wooden spoon or something smaller, such as a kebab. Spread the yogurt evenly over the surface of the cake, trying to get the yogurt into the holes as much as possible. Top with an even layer of the Cool Whip. Refrigerate for at LEAST 3 hours or until set, preferably allowing time to set overnight (the flavors are better this way!). Cut into squares and serve.