America's Test Kitchen Coconut Layer Cake Recipe

How to Make America's Test Kitchen Coconut Layer Cake

1. Adjust oven rack to lower-middle position and heat oven to 325°F (160°C).
2. Grease and flour two 9-inch round cake pans.
3. In a large measuring cup, whisk together 2 large egg whites and 2 large whole eggs.
4. Add 1 (13.5 ounce) can of cream of coconut, 1/2 cup water, 1 teaspoon vanilla extract, and 1/2 teaspoon coconut extract. Whisk until well combined.
5. In a stand mixer fitted with the paddle attachment, whisk together 2 1/2 cups all-purpose flour, 2 1/2 cups granulated sugar, 4 teaspoons baking powder, and 1 teaspoon salt.
6. With the mixer on low speed, gradually add 1 cup (2 sticks) unsalted butter, one piece at a time, mixing until the mixture resembles coarse crumbs.
7. With the mixer still running on low speed, add 1 cup of the wet coconut mixture.
8. Increase speed to medium-high and beat until light and fluffy (about 45 seconds).
9. With the mixer running, gradually add the remaining 1 cup of wet coconut mixture.
10. Stop the mixer, scrape down the bowl, and beat on medium-high speed for 15 seconds.
11. Divide batter evenly between the prepared cake pans.
12. Bake for 30 minutes, or until a toothpick inserted into the center comes out clean and the cakes pull away from the sides of the pans.
13. Do not turn off the oven.
14. Let cakes cool in pans on wire racks for 10 minutes.
15. Run a paring knife around the edges of the cakes, invert onto racks, and then re-invert to cool completely.
16. While cakes are cooling, spread 1 cup shredded sweetened coconut on a rimmed baking sheet.
17. Toast in the oven (still at 325°F) for 15-20 minutes, stirring 2-3 times, until golden brown and white shreds are mixed.
18. Let toasted coconut cool completely.
19. For the buttercream frosting: In a heatproof bowl, whisk together 4 large egg whites, 1 1/2 cups granulated sugar, and a pinch of salt.
20. Set the bowl over a saucepan of barely simmering water (1 1/2 inches of water).
21. Whisk constantly until the mixture is opaque, warm to the touch, and registers 120°F (49°C) on an instant-read thermometer (about 2 minutes).
22. Transfer the bowl to a stand mixer fitted with the whisk attachment.
23. Beat on high speed until barely warm, glossy, and sticky (about 7 minutes).
24. Reduce speed to medium-high and add 1 cup (2 sticks) unsalted butter, one piece at a time.
25. Beat in 1 (13.5 ounce) can cream of coconut, 1 teaspoon coconut extract, and 1 teaspoon vanilla extract.
26. Stop the mixer, scrape down the bowl, and beat on medium-high speed until well combined (about 1 minute).
27. To assemble: Cut each cake layer in half horizontally.
28. Place a dollop of frosting on a cardboard round. Top with a cake layer.
29. Frost the top with a generous amount of frosting, spreading to the edges.
30. Repeat with remaining layers.
31. Frost the sides of the cake, using an icing spatula to create a smooth finish.
32. Sprinkle the top and sides with the toasted coconut flakes.