Preheat the oven to 350. Spray and flour a 9x9 baking dish that has at least 2-inch high sides.
Mix flour and baking powder in a bowl. Set aside.
Using a whisk attachment on your electric mixer, whip egg whites until frothy, on medium-high speed. With the mixer running, slowly add sugar and beat until stiff peaks appear. Beat in egg yolks, 1 at a time, mixing well after each addition.
Add flour mixture in 3 parts, alternating with milk. Scrape sides and bottom of the bowl, mix a few more seconds to combine.
Pour the batter into prepared pan. Spread pineapple chunks all over the top of the batter (it's okay if they start to drown.). Bake for 38-43 minutes. Use a toothpick, inserting it into the center of the cake to see if it comes out clean.
Cool the cake for about 10 minutes. Run a lightly greased butter knife between the cake and the pan, to separate it. Gently invert onto a large platter and cool to room temperature.
Pierce the top of the cake all over with a large fork.
Mix sweetened condensed milk, evaporated milk, and coconut milk. Start pouring the mixture very slowly, all over the cake. Taking breaks for the liquid to soak through a bit.
Cover and refrigerate for at least 3 hours. (You can refrigerate overnight and finish the cake the next day.)
Whipped Cream: Add the cold heavy whipping cream in the cold mixing bowl. (Use a whisk attachment for your electric mixer.) Starting at low speed, start whisking, gradually raise to speed to high. Slowly pour in the sugar. Beat until stiff peaks appear (don't walk away far, this will be quick). Keep in the refrigerator until ready to use.
Spread whipped cream evenly over the top of the cake. Spread coconut flakes all over the top and then, crushed pineapple chunks over that. You can also decorate with some cherries.