Prepare cake batter according to the directions on the box.
Beat in the drained oranges until blended.
Pour into two greased and floured 9-in. round baking pans.
Bake at 350° for 22-25 minutes or until a toothpick inserted near the center comes out clean. Cool for 10 minutes and then transfer from the pans to wire racks to cool completely.
In a bowl, combine the drained pineapple and dry vanilla pudding mix.
Fold in the Cool Whip.
Spread some of the frosting on the top of one layer.
Then put the other layer of cake on top of that. Spread the remaining frosting on the top and sides of the cake. Garnish with mandarin oranges or pineapple chunks, if desired.
Store this cake in the refrigerator.
The calories shown are based on the cake being cut into 12 pieces, with 1 serving being 1 slice of cake. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate.