Preheat your oven according to the white cake mix box instructions. In a large mixing bowl, combine the white cake mix with 1.25 cups coconut milk, vanilla extract, and salt. Mix until just combined according to package directions—don't overmix, as this will develop gluten and make the cake tough. Pour the batter into a prepared 9x13 inch baking dish (or whatever size the box recommends) and bake according to the box instructions until a toothpick inserted in the center comes out clean. I always use Betty Crocker Super Moist because it gives you that tender, moist crumb right from the start.

Remove the cake from the oven and let it cool for about 5 minutes—it should still be warm but cool enough to handle. Using a fork or wooden skewer, pierce the entire surface of the cake all over, creating small holes throughout. This allows the cream of coconut to soak in deeply and infuse every bite. Heat the cream of coconut in the microwave on high for 1.5 minutes until it's warm and pourable. Slowly pour the warm cream of coconut evenly over the entire cake, allowing it to seep through the holes. I find that warming the cream of coconut first helps it absorb more effectively and distributes the flavor more evenly.

Cover the cake loosely with plastic wrap or foil and refrigerate for several hours, or preferably overnight. This resting time allows the coconut liquid to fully absorb throughout the cake, making it incredibly moist and flavorful, while also helping the cake structure set firmly before frosting.

Remove the cake from the refrigerator and spread the thawed whipped topping evenly over the entire surface using an offset spatula or the back of a spoon. Top with the flaked coconut, pressing it gently into the frosting so it adheres. Serve chilled or at room temperature. Make sure your whipped topping is completely thawed before using—this makes it much easier to spread smoothly without tearing the delicate cake.