Preheat your oven to 180 C (350 F) and grease a 9x13 baking pan with butter.
In a mixing bowl, add the Cake ingredients.
Beat with an electric mixer on low speed for 2 minutes.
Pour into the prepared pan, bake for 25-30 minutes or until a toothpick inserted in the center comes out clean.
Cool cake on a wire rack until completely cooled.
When the cake is completely cooled, add the pineapple and pudding mix to a mixing bowl, mix together, the pudding mix soaks up the juice.
Fold in the whipped topping until just mixed.
Spread the topping over the cake, cover, and place in the fridge for at least 1 hour before serving.
Optionally, add some mandarin orange segments to the top, or pineapple tidbits, each one well drained, then place in the fridge.
Cut into squares, serve, and enjoy.