Let’s get baking! Here’s a detailed, step-by-step guide:

Part 1: Make the Cake

1. Preheat Oven and Prepare Pans: Preheat the oven to 350°F (175°C). Butter three 8-inch round cake pans and line the bottoms with parchment paper rounds. Butter the parchment paper, then dust the pans with all-purpose flour and tap out the excess.

2. Combine Dry Ingredients: Whisk together the all-purpose flour, cake flour, baking powder, and salt in a medium bowl. Set aside.

3. Cream Butter and Sugar: In a large bowl, using a mixer on medium speed, beat the softened butter and sugar until pale and fluffy, 3 to 5 minutes.

4. Add Eggs and Extracts: Add the eggs and egg whites one at a time, beating well after each addition and scraping down the bowl as necessary. Beat in both the coconut extract and vanilla extract.

5. Alternate Adding Dry Ingredients and Milk: Reduce the mixer speed to low and gradually beat in the flour mixture in three batches, alternating with the milk, beginning and ending with the flour. Beat until just incorporated. Do not overmix.

6. Divide Batter and Bake: Divide the batter evenly among the prepared cake pans. Bake until the cakes are golden brown around the edges and a toothpick inserted into the centers comes out clean, 40 to 45 minutes.

7. Cool: Transfer the cake pans to wire racks and let the cakes cool in the pans for 15 minutes. Then, invert the cakes onto the racks, remove the parchment paper, and let them cool completely.

Part 2: Make the Frosting

1. Make Meringue Base: While the cakes are cooling, make the frosting. Combine the sugar and egg whites in a heatproof bowl (the bowl of a stand mixer works well) set over a pan of simmering water. Do not let the bottom of the bowl touch the water. Whisk constantly until the mixture is warm to the touch and the sugar is completely dissolved, 3 to 4 minutes.

2. Beat Meringue: Remove the bowl from the heat and beat the mixture with a mixer on medium speed until it’s thick and glossy, about 5 minutes.

3. Whip to Stiff Peaks: Increase the mixer speed to medium-high and beat until stiff peaks form and the bottom of the bowl is cool to the touch, about 7 more minutes.

4. Add Butter: Reduce the mixer speed to medium-low. Add the softened butter, a few tablespoons at a time, beating well after each addition. It’s okay if the frosting looks separated at first – just keep beating on medium-high speed until it comes back together and is smooth.

5. Add Extracts and Salt: Add the coconut extract, vanilla extract, and salt. Continue beating until the frosting is light and fluffy, 3 to 5 minutes.

Part 3: Assemble the Cake

1. Trim Cake Layers (Optional): If necessary, trim the tops of the cooled cake layers with a long serrated knife to make them level.

2. First Layer: Place one cake layer on a cake stand or platter. Spread with 1 cup of frosting.

3. Second Layer: Place the second cake layer on top of the frosting. Spread with another 1 cup of frosting.

4. Third Layer and Frost: Place the remaining cake layer on top. Spread the remaining frosting over the top and sides of the entire cake.

5. Coat with Coconut: Press the shredded coconut into the sides of the cake, coating it completely.

Serve and enjoy this stunning and delicious Coconut Layer Cake!