Preheat your oven to 350 degrees F. Grease the inside of a 9-inch x 13-inch baking dish with non-stick cooking spray.
Prepare the cake mix according to the package directions. Pour the batter into the prepared baking dish. Bake according to package instructions for a 9x13 dish.
Once the cake is done baking, remove it from the oven and poke holes all over the top of the cake with the back of a wooden spoon or a fork. Set aside.
In a medium mixing bowl, whisk together the sweetened condensed milk and coconut milk. Slowly pour the mixture all over the warm cake. Let the cake cool to room temperature and then transfer to the fridge for at least 1 hour to cool completely.
While the cake rests, whisk the instant coconut pudding mix and milk together according to the package directions. Once thickened, place the pudding in the fridge.
Once the cake has cooled completely, spread the pudding over the top of the cake in an even layer. Then, spread the Cool Whip over the pudding.
Sprinkle the toasted coconut all over the top of the cake. Cut into 12 slices and serve.
Notes
Oven Toasted Coconut: Preheat your oven to 325 degrees F. Spread the coconut flakes out on a baking sheet in a thin layer and bake for 5-10 minutes, stirring every few minutes. When coconut is toasted to your liking, transfer it to a bowl to cool.Stovetop Toasted Coconut: Place a large skillet over medium-low heat. Add the coconut and cook, stirring often, until it's toasted to your liking. Transfer the coconut to a bowl to cool.