Gather the ingredients - * White cake mix * Coconut milk * Crushed pineapple * Vanilla pudding * Rum (optional) * Cool whip * Shredded coconut
Prepare cake mix according to the instructions on the back of the box in a lightly greased 9x13 baking dish.
In a large bowl, stir together the coconut milk, crushed pineapple (including the juices), vanilla pudding mix, and rum (optional) until well combined.
As soon as the cake is done baking, a straw or chopstick to poke holes all over the surface of the cake, then pour the pineapple mixture over the top. Smooth with the back of a spoon.
Allow the cake to cool to room temperature before placing in the refrigerator to chill for at least 3 hours.
Before serving, spread the cool whip on top and sprinkle with shredded coconut.