Start by moving your oven rack to the lower third part of your oven and preheat it to 375 degrees. In a separate bowl, mix together 1 cup of cake flour and 3/4 cup of sugar and set to the side.
In the mixing bowl, add 1 tbsp of lemon juice and 12 egg whites. Start mixing at low speed until the egg whites start to turn foamy. Then add 1 tsp cream of tartar, 1/4 tsp of salt, 1/2 tsp of vanilla, and 1/8 tsp of coconut extract. Turn your mixer up to medium-high speed and continue whipping until soft peaks form.
(Save 3 egg yolks for the curd.)
While the mixer is still going, add the 3/4 cup sugar a tbsp at a time. Turn the mixer up to high speed and whip until a stiff, shiny meringue forms. Do not overwhip, once the egg whites hold a peak stop mixing or your cake will sink in the oven while baking.
Take the mixing bowl off the stand and sift 1/3 of the flour mixture over the top of the meringue. Use a large rubber spatula to gently fold in the flour. Repeat two more times until all the flour is incorporated. Carefully scoop the batter into the ungreased 10" angel food cake pan and delicately even out.
Place the pan in the oven and bake for 30-40 minutes. The cake is finished when it's golden brown and springs back when you lightly poke it. Once it's finished baking, immediately turn the pan upside down and let it cool like that on the cooling rack for at least 1 hour. Once the hour is up, use a knife to carefully separate the sides and middle from the pan. Flip the pan upside down again and tap on the top to get the cake to release. Once it's out of the pan finish cooling completely on the cooling rack before frosting.