Step 1Mix and bake cake mix as per package instruction for two 8 or 9 inch round layers. Let layers cool, and then split each layer in half so as to have 4 layers.Step 2In a large bowl, whip cream cheese until soft, and then gradually mix in confectioners' sugar. Stir in the pineapple with juice and the drained mandarin oranges, reserving about 5 mandarin orange slices to decorate the top of cake. Mix in the dry pudding mix. Fold in the whipped topping.Step 3Place one cake layer on a cake plate cut side up; spread with frosting. Place another layer cut side down on the first one, and top with more frosting. Repeat until all layers are used, spreading last bit of frosting on top and sides of cake. Decorate with reserved mandarin orange slices. Refrigerate overnight before serving.