Preheat your oven according to the yellow cake mix package instructions, typically around 350°F (175°C). Grease a 9×13 inch baking pan and prepare the cake batter according to the package directions. Pour the mixture into the pan and bake for 25-30 minutes until a toothpick inserted in the center comes out clean. Allow the cake to cool completely on a wire rack before proceeding.

In a medium bowl, combine the crushed pineapple with its juice and half of the sweetened shredded coconut. Stir the mixture gently until well blended. Set aside.

Once the cake has cooled completely, use the handle of a wooden spoon to poke holes evenly across the surface of the cake. Pour the pineapple mixture over the cake, ensuring it spreads evenly.

In a separate bowl, whisk together the instant vanilla pudding mix and cold milk until smooth and thickened, which typically takes about 2-3 minutes. Carefully spread the pudding mixture over the pineapple layer.

Gently spread the thawed whipped topping over the pudding layer. Sprinkle the remaining sweetened shredded coconut on top.

Cover the cake and refrigerate for at least 4 hours or ideally overnight.