Pre-heat oven to 350 degrees F. Butter and flour a 9X13-inch cake pan. Sift flour, baking powder, baking soda, and the salt together in a bowl, and set aside.
In the bowl of an electric mixer, beat the 1 pound of butter on medium speed for 1 minute. Add 2 1/2 cups sugar, and the 7 egg yolks, one at a time, beating after each addition. Add 1 tablespoon vanilla extract and beat until mixture is fluffy, about 3 minutes. Lower the speed and mix in half the dry ingredients. Add the milk, then the remaining dry ingredients.
In a separate bowl, whip the 7 egg whites with the cream of tartar until soft peaks form. Fold about one third of the whites into the cake batter to loosen up the batter and prevent the whites from breaking down. Add the remaining whites, folding in gently until incorporated. Pour the batter into the prepared cake pan and bake in the preheated oven for abut 35 minutes, or until a skewer inserted into the cake comes out clean.
In a medium bowl, combine coconut cream with sweetened condensed milk and stir until smooth. When the cake comes out of the oven, quickly poke holes into it in even rows using the handle of a wooden spoon, then pour the milk and coconut cream mixture over and allow to soak into the cake. Refrigerate for several hours or overnight.
After cake has cooled in refrigerator, top with the thawed cool whip, making decorative swirls, etc. Then sprinkle flaked or shredded coconut over all and decorate as desired.