Preheat your oven to 350°F (175°C).

Grease and flour two 9-inch round cake pans or line them with parchment paper.

In a large mixing bowl, combine the cake mix, orange soda (or juice), vegetable oil, and eggs.

Beat on medium speed for 2 minutes, or until the batter is smooth and well combined.

Divide the batter evenly between the prepared pans.

Bake for 25–30 minutes, or until a toothpick inserted into the center comes out clean.

Let the cakes cool in the pans for 10 minutes, then transfer to a wire rack to cool completely.

In a medium bowl, whisk together the vanilla pudding mix, cold milk, and orange extract (if using) until thickened.

Gently fold in the whipped topping until the frosting is smooth and creamy.

Place one cake layer on a serving plate and spread a layer of frosting over the top.

Add the second layer and spread the remaining frosting evenly over the top and sides of the cake.

Decorate the cake with orange zest, orange slices, or white chocolate shavings for a festive touch.

Chill the assembled cake in the refrigerator for at least 1 hour to allow the flavors to meld.

Slice and serve chilled for the best flavor and texture.