Step 1

Preheat oven to 350 degrees Fahreinheit. Spray three 9 inch round cake pans with nonstick spray.

Step 2

For the Cake: Mix the cake mix, vanilla instant pudding mix, vegetable oil, milk, sour cream and eggs with an electric or stand mixer until fluffy (about 2 minutes on medium speed).

Step 3

Pour the cake batter evenly into your 3 prepared cake pans.

Step 4

Bake for 25-27 minutes or until a wooden pick inserted in the center of the cake comes out clean.

Step 5

Cool on a wire rack 5 to 10 minutes before inverting. Allow to cool completely before frosting.

Step 6

For the frosting: Whisk milk and pudding until pudding begins to get thick. Fold in Cool Whip and orange zest until well combined. Fold carefully to keep it light and fluffy.

Step 7

Wait until the cake is completely cool before frosting. For a more professional cake, remove the domes from the tops of the cake layers with a cake leveler or large serrated knife. Place one layer of cake on a serving plate. Spread about 1 cup of the frosting on top in an even layer. Repeat with the next layer of cake and frosting, then top the cake with the final layer of cake (if you have 3 layers). Frost the outside of the cake. An offset spatula makesit really easy to get an even layer.