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.

Beat the butter and sugar together on medium-high speed until smooth and creamy, about 2 minutes. Scrape down the sides as needed.

Beat in the egg whites until combined, then add the sour cream, vanilla extract, and coconut extract. Beat until combined.

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 at the bottom of the bowl.

Pour batter evenly into cake pans. Bake for 21–24 minutes or until a toothpick inserted into the center comes out clean.

Allow cakes to cool in the pans set on a cooling rack for 1 hour, then remove from the pans and place on the rack to continue cooling.

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

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

If desired, adjust frosting consistency with more confectioners’ sugar or coconut milk.

Slice a thin layer off the tops of the cakes to create a flat surface.

Place 1 cake layer on a cake stand or serving plate. Evenly cover the top with 1 heaping cup of frosting.

Top with the second cake layer and evenly cover the top with another heaping cup of frosting.

Top with the third cake layer. 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.