01 - Preheat oven to 350°F. Grease a 9x13-inch baking pan with cooking spray or butter.
02 - Combine yellow cake mix, eggs, crushed pineapple with juice, vegetable oil, and water in a large bowl. Beat with electric mixer on medium speed for 2 minutes until batter is smooth and well combined.
03 - Pour batter into prepared baking pan. Bake for 28-32 minutes until a toothpick inserted in center comes out clean. Cool cake in pan for 10 minutes.
04 - Using the handle of a wooden spoon, poke holes all over the warm cake, spacing about 1 inch apart. Press holes about three-quarters of the way through the cake.
05 - Whisk sweetened condensed milk and coconut milk together in a medium bowl until thoroughly combined and smooth.
06 - Slowly pour milk mixture evenly over the warm cake, ensuring liquid fills the poke holes. Allow cake to absorb mixture for 5 minutes.
07 - Whisk instant vanilla pudding mix, cold milk, and pineapple juice in a separate bowl for 2 minutes until pudding begins to thicken. Spread evenly over cake.
08 - Cover baking pan with plastic wrap or foil. Refrigerate for at least 1 hour or until completely chilled and set.
09 - Spread thawed whipped topping evenly over the chilled cake using an offset spatula.
10 - Sprinkle toasted coconut generously over the top. Garnish with fresh pineapple chunks and maraschino cherries if desired. Slice into 12 squares and serve cold.