Grease & flour coat a 9"x13" baking pan. Prepare white cake mix using 4 egg whites and oil & water as indicated on the box instructions. Beat the cake mix on high for 90 seconds.
Open can of crushed pineapple and press lid in to squeeze juice into a measuring cup. You should extract approx. 2/3 cup of juice. Set this aside for the frosting.
Add crushed pineapple and 1/2 a bag of the shredded coconut to the cake mix and blend together on low speed and then beat at higher speed for 90 seconds.
Pour batter into prepared pan and place in center of pre-heated oven at 350 degrees for 40-45 minutes - do the toothpick test to verify doneness. Remove cake from oven and let cool in pan on cooling rack for 15 minutes. Then remove cake from pan to cookie sheet or serving platter and let cool completely. While it's cooling, make your frosting.
Cream Cheese Frosting: Blend together the softened cream cheese, pineapple juice, 1/2 stick butter, egg white, & teaspoon of Coconut extract. Once creamy, begin to add in sifted 10x sugar (5-6 cups) on low speed. The frosting will be on runny side, don't panic. Once mixed, place the bowl of frosting in a cold fridge for about 30 minutes before applying it to the cake. The yield of frosting will be quite a lot, so I use what I want to frost the cake and freeze the rest for the next time I make this cake. Coat the cake with the frosting and sprinkle some more shredded coconut on top if desired. Cake must be refrigerated at all times because of the cream cheese based frosting. Enjoy!