01 - Preheat oven to 350°F. Grease a 9x13-inch baking pan thoroughly.
02 - In a large bowl, combine yellow cake mix, eggs, crushed pineapple with juice, vegetable oil, and water. Beat until completely smooth and well incorporated.
03 - Pour batter into prepared baking pan. Bake for 28-32 minutes or until a toothpick inserted into the center comes out clean.
04 - Allow cake to cool for 10 minutes. Using the handle of a wooden spoon, poke holes evenly across the entire cake surface, spacing approximately 1 inch apart.
05 - In a medium bowl, whisk together sweetened condensed milk and coconut milk until thoroughly combined. Slowly pour mixture evenly over the warm cake, allowing it to absorb into the holes.
06 - In a separate bowl, whisk together instant vanilla pudding mix, cold milk, and pineapple juice until mixture begins to thicken, about 2 minutes. Spread evenly over the cake surface.
07 - Cover baking pan with foil or plastic wrap. Refrigerate for at least 1 hour until completely chilled and set.
08 - Remove cake from refrigerator. Spread thawed whipped topping evenly over the entire surface of the chilled cake.
09 - Sprinkle toasted shredded coconut generously over the whipped topping. Arrange fresh pineapple chunks and maraschino cherries on top if desired.
10 - Cut into 12 even squares. Serve immediately while cold, or return to refrigerator until ready to serve.