Coconut Cake w/Guava Curd & Meringue Buttercream
4 1/4 cups all-purpose flour
2 1/4 cups sugar
1 tablespoon plus 1 1/2 teaspoons baking powder
2 teaspoons kosher salt - I used one tsp
2 sticks unsalted butter, softened
1 1/4 cups unsweetened coconut milk
3/4 cup water
2 teaspoons pure vanilla extract
6 egg whites
3/4 cup sugar
1/4 cup cornstarch
1 cup guava puree
4 egg yolks
1 vanilla bean—split, seeds scraped ( I omitted this step)
1 stick unsalted butter, cut into tablespoons
5 eggs (large)
10 ounces (1 1/4 cups) extra-fine granulated sugar, divided
1/4 cup water
1 pound (4 sticks) unsalted butter, soft
Preheat the oven to 350°. Line the bottom of three 8-inch square or round cake pans with parchment paper and spray with nonstick cooking spray. In the bowl of a stand mixer fitted with the paddle, mix the flour, sugar, baking powder and salt at low speed. Mix in the butter, coconut milk, water and vanilla until combined. Scrape down the bowl and beat at high speed until very smooth, 2 minutes.
In a medium bowl, using an electric mixer, beat the egg whites until soft peaks form, 2 minutes. Fold half of the egg whites into the batter until incorporated, then fold in the remaining whites until no streaks remain. Divide the batter among the cake pans. Bake for about 45 minutes, until a toothpick inserted in the centers comes out clean. Cool the cakes in the pans on a rack for 15 minutes, then invert them and let cool completely, about 2 hours.
In a saucepan, whisk the sugar and cornstarch. Whisk in the guava puree, egg yolks and vanilla seeds and cook over moderate heat, stirring constantly, until thick, 6 minutes. Remove from the heat; whisk in the butter, 1 tablespoon at a time, until incorporated. Scrape the filling into a glass bowl, press a sheet of plastic wrap on the surface and refrigerate until chilled, about 2 hours.
Using a serrated knife, cut each cake in half horizontally to create 6 layers. Set one layer on a cake plate. Spread with 6 tablespoons of the filling. Repeat with the remaining 5 cake layers and filling, ending with a layer of cake. Refrigerate until firm, 1 hour.
Separate the eggs and place the whites in the bowl of the standing mixer fitted with a wire whip attachment. Reserve the yolks for another use. Measure 1 cup of the sugar into a heavy-bottomed 1-quart saucepan with 1/4 cup water. Gently stir to combine; I use the candy thermometer for this. Leave the candy thermometer in the saucepan, numbers facing down to balance the thermometer. Measure the 1/4 cup sugar into a small bowl and set aside. Cut the butter into tablespoon-size pieces and set aside in a medium bowl.
Begin making the sugar syrup. Place the saucepan with the sugar and water over medium-high heat. Partially cover with a lid to capture the evaporating water -- this helps to moisten the sides of the saucepan to prevent sugar crystals separating from the syrup.
Begin whipping the egg whites to stiff peak in a standing mixer fitted with the wire whip attachment set to high speed. When the whites are at stiff peak you have a meringue. Keep the mixer running and pour the 1/4 cup of sugar into the meringue.
Raise the heat to bring the syrup to 245 degrees if it is not there already. When the syrup is at 245 degrees, remove the thermometer and slowly pour the syrup into the meringue.
When pouring, keep your eye on the bowl. Aim for the space between the mixer bowl and the revolving wire whip. After 1 to 2 minutes reduce the speed to medium for about 3 to 4 minutes or until the meringue is cooled.
Add the butter one tablespoon at a time. Increase the speed to high for one to two minutes to fully combine the butter with the meringue.