Heat oven to 350°F (325°F for dark or nonstick pan). Spray bottom only of 13x9-inch pan with baking spray with flour.
In large bowl, beat cake mix, eggs, 1 cup water and the oil with electric mixer on low speed 30 seconds. Beat on medium speed 2 minutes, scraping bowl occasionally. Pour batter into pan
Bake 28 to 33 minutes or until toothpick inserted near center comes out clean. Cool completely in pan on cooling rack, about 1 hour.
Poke cake all over with fork or wooden skewer. In medium bowl, pour boiling water on 1 box orange gelatin; stir until gelatin is dissolved. Stir in cold water. Pour gelatin over cake. Run knife around edges of pan to loosen cake. Refrigerate 2 hours.
In a large mixing bowl, beat cream cheese until smooth with electric hand mixer (or other); add orange jello, instant vanilla pudding, 1 cup milk, orange and vanilla extract. Immediately beat until smooth and well blended. (Don't let the jello and vanilla pudding sit or they'll get lumpy). Fold in Cool whip.
Spread over the cake and keep refrigerated until serving. Garnish with additional whipped topping and orange peel. Refrigerate any leftovers.