Prepare oven and pans. Preheat the oven to 350°F. Prepare three 9″ inch cake pans by lightly greasing them and then dusting with flour. Cut a piece of parchment paper to fit in the bottom of each pan.
Make batter. Mix the cake mix, sour cream, vegetable oil, eggs, and cream of coconut in a large mixing bowl. I like to use my stand mixer with the paddle attachment on medium-high speed but you can also use an electric hand mixer or just mix it together by stirring with a spatula.
Fill pans. Divide cake batter evenly between the 3 prepared pans. Each pan should be filled to slightly higher than 1/2 to ensure that the cake does not overflow as it bakes. You may have extra batter.
Bake. Place the filled cake pans in the oven and bake for approximately 30 minutes at 350°F or until you can put a toothpick in the center and it comes out clean.
Make the frosting. While the cake bakes make the frosting by combining powdered sugar and cream cheese together in the bowl of your mixer. You will need an electric mixer with a whisk attachment for the frosting so you can whip everything together into light fluffy frosting.
Cool. Remove the cakes from the oven and let them cool for 10-15 minutes in the pan. Then gently remove the cake from the pans and let it finish cooling on a wire rack until the layers reach room temperature.
ASSEMBLING THE CAKE 1. Place one 9 inch round cake on a cake board (this will make it easier to move cake to the freezer. If you are not freezing it you can skip this step and instead place it on your cake stand or your cake carrier bottom. 2. Frost the top of the layer and place the next layer of cake on top. Frost the top of that layer and place the third and final layer on top. 3. Frost the top and sides of the cake. 4. Press coconut into sides and onto top of cake. 5. Once cake is frosted wrap it in plastic wrap and then aluminum foil and place in the freezer. Take it out to thaw at least 4 hours before you are ready to serve.