NOTE: It is SUPER IMPORTANT that all the room temperature ingredients listed above are room temperature and not cold so that the ingredients mix and incorporate correctly.
Adjust an oven rack to the middle position and preheat to 350ºF/176ºC. Prepare three 8"x2" round cake pans with cake goop or another preferred pan release.
Spread your coconut flakes evenly onto a cookie sheet pan and bake for 2-3 minutes or until they JUST start to turn brown around the edges. Stir the coconut and bake for 1-2 minutes more until lightly golden. Watch closely or it could burn. Remove from the oven and let cool.
Whisk together the flour, baking powder, baking soda and salt in a medium bowl. Set aside.
Add the oil, coconut extract and vanilla extracts to your buttermilk
Place egg whites in a mixing bowl with the whip attachment. Whip on med-high. Add in cream of tartar. Whip until firm but moist peaks form. Set aside
Add butter to stand mixer with the paddle attachment and beat at medium-high speed until smooth and shiny, about 30 seconds. Gradually sprinkle in the sugar, beat until mixture is fluffy and almost white, about 3-5 minutes.
Add egg yolks, one at a time to the mixture, beating well after each until combined.
With the mixer at the lowest speed, add about a third of the dry ingredients to the batter, followed immediately by about a third of the milk, mix until ingredients are almost incorporated into the batter. Repeat the process 2 more times. When the batter appears blended, stop the mixer and scrape the sides of the bowl with a rubber spatula.
Fold in your whipped egg whites and toasted coconut gently.
Divide the batter evenly between the prepared pans. Smooth the tops with a rubber spatula. Bake cakes until they feel firm in the center and a toothpick comes out clean or with just a few crumbs on it, about 25-30 minutes.
Transfer pans to a wire rack and let cool for 10 minutes. Invert cakes onto the rack and pop cakes out of pans. Cool completely before frosting.