Preheat oven to 350°F (177°C). Grease three 8-inch cake pans, line with parchment paper rounds, then grease the parchment paper.

Whisk the cake flour, baking powder, baking soda, and salt together. Set aside.

Using a handheld or stand mixer, beat the butter and sugar together on medium-high speed until smooth and creamy, about 2 minutes. Scrape down the sides and bottom of the bowl as needed.

Beat in the egg whites until combined, then add the sour cream, vanilla extract, and coconut extract. Beat until combined; the mixture will look curdled.

With the mixer on low speed, slowly add the dry ingredients and coconut milk. Beat on low speed until combined, then add the shredded coconut. Whisk by hand to ensure there are no butter lumps.

Pour batter evenly into the prepared cake pans. Bake for 21–24 minutes or until a toothpick inserted into the center comes out clean. Cool in the pans for 1 hour, then transfer to a cooling rack.

In a large bowl, beat the butter and cream cheese together on medium speed until creamy and smooth, about 2 minutes.

With the mixer running on low, add the confectioners’ sugar, coconut milk, vanilla extract, coconut extract, and salt. Increase to high speed and beat for 3 minutes.

Slice a thin layer off the tops of the cooled cakes to create a flat surface. Place one cake layer on a cake stand or serving plate. Evenly cover the top with about 1 heaping cup (about 250–300g) of frosting.

Add the second cake layer and cover the top with another heaping cup of frosting. Top with the third cake layer and spread the remaining frosting all over the top and sides.

Sprinkle coconut on top of the cake and apply it to the sides. Refrigerate the cake for at least 20 minutes before slicing.