Step 1

Preheat the oven and prepare the cake pans. Arrange a rack in the middle of the oven and heat to 375°F. Spray 2 (9-inch) round cake pans with cooking spray. Cut two rounds of parchment paper and line the cake pans; set aside.

Step 2

Whisk together the dry ingredients. Place the cake flour, baking powder, and salt in a medium bowl and whisk to combine; set aside.

Step 3

Cream together the butter and sugar. Place the butter and 1 2/3 cups of the sugar in the bowl of a stand mixer fitted with a paddle attachment. (Alternatively, use an electric hand mixer and large bowl.) Beat on medium-high speed until lightened in color, increased slightly in volume, and creamy looking, 3 to 4 minutes. Scrape down the sides of the bowl with a rubber spatula.

Step 4

Add the dry ingredients, alternating with the coconut milk. Beat in the flour mixture in 3 increments and the coconut milk in 2 increments: Beat in the first 1/3 of the flour mixture on low speed until incorporated. Add 1/2 of the coconut milk and beat until smooth. Stop the mixer and scrape down the bowl with a spatula. Repeat adding another 1/3 of the dry mixture on low speed, followed by the coconut extract and the remaining coconut milk. Finish by beating in the remaining flour mixture until just combined.

Step 5

Whip the egg whites and remaining sugar. If you don’t have a hand mixer, transfer the batter to a large bowl, then wash and dry the stand mixer bowl. (If using a hand mixer, use a large bowl.) Place the egg whites, cream of tartar, and remaining 1/3 cup sugar in the bowl and whip with the whisk attachment on medium-high speed until medium peaks have formed — the mixture should hold a slightly arched peak when the whisk is removed from the mixture.

Step 6

Fold the whipped egg whites into the cake batter. Here’s the hardest part of this recipe: adding the light, fluffy egg whites to the thick batter without losing their volume. Start by sacrificing some of the egg whites: Add 1/3 of the egg whites into the batter and quickly fold them into the batter to loosen it. Then work carefully to “fold” the remaining egg whites into the batter in 2 batches. Folding is gently turning a wide spatula over and then up and under the batter to incorporate, turning the bowl after each fold to incorporate evenly.

Step 7

Pour the batter into the prepared pans and bake for 30 minutes. Divide the cake batter between the two pans. Bake until lightly golden-brown and the cakes spring back when touched and pull away from the sides, 30 to 35 minutes.

Step 8

Cool the cakes. Place the cakes on a cooling rack and cool for 10 minutes. Flip the cakes out of the pans onto the rack, discard the parchment, and let cool completely, about 1 hour. If you aren’t frosting the cakes right away, tightly wrap in plastic wrap to prevent the cakes from drying out and store at room temperature for up to 2 days.

Step 9

Make the frosting. Bring a quart of water to a boil in a 4-quart pot. Reduce the heat to maintain a simmer. Place the sugar, egg whites, coconut water, and cream of tartar in a heatproof medium bowl that will fit onto the pot of water without the bottom touching the water. Place the bowl over the simmering water and mix with an electric hand mixer on low speed until combined. Increase the speed to high and whip for 5 minutes — the mixture will thicken, increase in volume, and become glossy. Remove the bowl from the heat, add the coconut extract, and beat on medium speed for 1 minute. Let the frosting cool for 5 minutes before frosting.

Step 10

Frost the cake. Smear a tablespoon of the frosting onto a cake plate. Center one cake layer on the plate. Evenly spread 1 cup of the frosting on the cake. Top with the second layer of cake. Dollop the remaining frosting on the top of the cake and spread the cake evenly over the top of the cake and down the sides.

Step 11

Cover the cake with coconut. Sprinkle the coconut over the top of the cake. Then, working with a handful of coconut at a time, gingerly press the coconut into the sides of the cake.

Step 12

Refrigerate the cake for 30 minutes before serving. Refrigerate the frosted cake for 30 minutes before slicing and serving.