Preheat your oven to 350°F (177°C) and grease three 12-inch pans, lining them with parchment rounds.
Mix cake flour, baking soda, baking powder, and salt in a bowl.
Use your mixer to beat sugar and unsalted butter until creamy at medium speed, then add egg whites, sour cream, coconut extract, and vanilla extract. Mix until blended.
Reduce the mixer's speed to low and mix wet ingredients with dry ingredients (Step 2), pineapple juice, and coconut milk, then fold in pineapple chunks and shredded coconut by hand.
Pour batter into pans and bake for 22 to 24 minutes. Cool in pans on wire racks.