01 -
Preheat oven to 350°F. In a large mixing bowl, combine cake mix, vegetable oil, mandarin oranges with juice, sugar, and eggs. Mix on medium speed for 2 minutes until smooth and fully incorporated.
02 -
Grease and flour three 9-inch round cake pans. Line bottoms with wax paper for easier removal.
03 -
Divide batter evenly among prepared pans. Bake for 20 minutes, or until a toothpick inserted in center comes out clean and cake springs back when lightly pressed.
04 -
Allow cakes to cool in pans for 10 minutes. Remove from pans and transfer to cooling racks. Cool completely before icing.
05 -
In a medium bowl, stir crushed pineapple with instant vanilla pudding mix until blended. Gently fold in Cool Whip until smooth. If icing is too thick, thin by adding reserved pineapple juice a tablespoon at a time.
06 -
Place one cake layer on serving plate. Spread a layer of pineapple icing evenly. Repeat with remaining layers and frost the top and sides of the assembled cake.
07 -
Refrigerate the frosted cake for at least 2 hours. Cake flavors develop further when chilled overnight before serving.