Coconut Cake

It was a Hit. A Big Hit. Despite many steps, it was well worth the effort. I promised the recipe if it turned out and here it is. It is an adaptation of Bobby Flay's Throwdown winner, a little of Bon Appetit, frosting from America's Test Kitchen. Here it is:

Coconut Layer Cake

Cake:
1	large egg
5	large egg whites
3/4	cup cream of coconut (usually found where they sell the booze mixes)
1/4	cup water
1	teaspoon vanilla extract
1 3	teaspoon coconut extract (McCormick's imitation works well) tablespoons coconut oil, melted and cooled
2 1/4	cups cake flour (9 ounces), sifted
1	cup granulated sugar
1	tablespoon baking powder
3/4	teaspoon table salt
8	tablespoons unsalted butter (1 stick), cut into 8 pieces, softened, but still cool
3	cups sweetened shredded coconut

1. Adjust oven rack to lower-middle position and heat oven to 325 degrees. Grease two 9-inch round cake pans with shortening and dust with flour.
2. Beat egg whites and whole egg in large measuring cup with fork to combine. Add cream of coconut, water, vanilla, coconut extract and coconut oil and beat with fork until thoroughly combined.
3. Combine flour, sugar, baking powder, and salt in bowl of standing mixer fitted with paddle attachment. Mix on lowest speed to combine, about 30 seconds. With mixer still running on lowest speed, add butter 1 piece at a time, then beat until mixture resembles coarse meal, with butter bits no larger than small peas, 2 to 2 1/2 minutes.
4. With mixer still running, add 1 cup liquid. Increase speed to medium-high and beat until light and fluffy, about 45 seconds. With mixer still running, add remaining 1 cup liquid in steady stream (this should take about 15 seconds). Stop mixer and scrape down bowl with rubber spatula, then beat at medium-high speed to combine, about 15 seconds. (Batter will be thick.)
5. Divide batter between cake pans and level with offset or rubber spatula. Bake until deep golden brown, cakes pull away from sides of pans, and toothpick inserted into center of cakes comes out clean, about 30 minutes (rotate cakes after about 20 minutes). Do not turn off oven.
6. Cool in pans on wire racks about 10 minutes, then loosen cakes from sides of pans with paring knife, invert cakes onto racks and then re-invert; cool to room temperature.
7. While cakes are cooling, spread shredded coconut on rimmed baking sheet; toast in oven until shreds are a mix of golden brown and white, about 15 to 20 minutes, stirring 2 or 3 times. Cool to room temperature.

Coconut Simple Syrup:

1 1/2 cups water

1 tablespoon granulated sugar
3/4 cup sweetened flaked coconut

Bring water and sugar to a boil. Stir in the coconut, remove from the heat and let sit for at least 30 minutes and up to 4 hours. Strain the liquid into a clean saucepan, bring to a boil and let cook until the mixture is slightly reduced, about 5 minutes. Let cool.

Coconut Custard:

3/8 cup whole milk

3/8 cup unsweetened coconut milk
1/4 vanilla bean, seeds scraped
2 large egg yolks
2 1/2 tablespoons granulated sugar
1 1/2 tablespoons cornstarch
1 teaspoons coconut extract
1/4 teaspoon pure vanilla extract

Combine the milks, vanilla bean and seeds in a medium nonreactive saucepan and bring to a simmer over low heat.

Whisk together the yolks, sugar and cornstarch in a large bowl. Slowly whisk the warm milk into the egg mixture then return the mixture to the pot over medium heat and bring to a boil, whisking constantly, until thickened. Scrape the mixture into a bowl and whisk in the rum and vanilla extract. Let cool to room temperature then cover with plastic wrap and refrigerate until cold, at least 2 hours.

Coconut Filling:

3/4 cup coconut custard (recipe above), cold

3/4 cup very cold heavy cream

Combine the custard and cream in a bowl and whip until soft peaks form.\

Buttercream:

3 large egg whites
3/4 cup granulated sugar
    pinch of table salt
3 sticks unsalted butter, each stick cut into 6 pieces, softened, but still cool
3 Tbsp cream of coconut
3/4 teaspoon coconut extract
3/4 teaspoon vanilla extract
 
Combine whites, sugar, and salt in bowl of standing mixer; set bowl over saucepan containing 1 1/2-inches of barely simmering water. Whisk constantly until mixture is opaque and warm to the touch and registers about 120 degrees on an instant-read thermometer, about 2 minutes.

Transfer bowl to mixer and beat whites on high speed with whisk attachment until barely warm (about 80 degrees) and whites are glossy and sticky, about 7 minutes. Reduce speed to medium-high and beat in butter 1 piece at a time. Beat in cream of coconut and coconut and vanilla extracts. Stop mixer and scrape bottom and sides of bowl. Continue to beat at medium-high speed until well-combined, about 1 minute.

To Assemble:

Using a long serrated knife, slice each cake horizontally into 2 layers. Reserve 1 of the flat bottom layers for the top of the cake. Place another layer on a cardboard round cut side up and brush with some of the coconut simple syrup. Spoon 1/3 of the coconut filling onto the cake and using a small offset metal spatula, spread it into an even layer, leaving a 1/2-inch border around the edge of the cake. Repeat with 2 more layers. Brush the cut side of the reserved cake layer with the remaining syrup. Place the layer cut side down on top of the cake.

Frost the sides and top of the cake with the buttercream. Pat the coconut onto the sides of the cake and sprinkle the remaining coconut on the top of the cake.