01 -
Preheat oven to 350°F. Position the rack in the center. Generously coat two or three 9-inch round cake pans with nonstick baking spray containing flour. Line the bottoms with parchment circles and spray again for easy release.
02 -
Place chopped semisweet chocolate in a heatproof bowl. Pour boiling water over the chocolate, let stand one minute, then whisk until smooth and completely melted. Cool slightly.
03 -
Using an electric mixer, whip egg whites on high speed until stiff peaks form, about 1 to 2 minutes. Transfer to a separate bowl and set aside. Clean the beaters.
04 -
In a medium bowl, whisk together all-purpose flour, cocoa powder, baking soda, and salt until well combined.
05 -
Beat softened butter and granulated sugar on medium-high speed until light and fluffy, approximately 3 minutes.
06 -
Add egg yolks one at a time to the creamed mixture, blending well after each addition. Add in the cooled melted chocolate and vanilla extract, beating until the mixture is smooth.
07 -
On low speed, alternately add flour mixture and buttermilk in three additions, beginning and ending with flour mixture. Mix just until incorporated after each addition.
08 -
Gently fold stiff egg whites into the batter by hand, maintaining as much air as possible for a tender crumb.
09 -
Divide the batter evenly among prepared pans. Bake for 25 to 30 minutes for three layers, or 35 to 40 minutes for two layers, until a toothpick inserted in the center comes out clean. Cool cakes in the pans for 15 minutes, then turn out onto wire racks to cool completely.
10 -
In a saucepan, whisk egg yolks, evaporated milk, and light brown sugar until blended. Add butter and cook over medium-low heat, stirring frequently, until thickened and golden, about 12 minutes. Remove from heat, then stir in coconut, chopped pecans, vanilla, and salt. Allow frosting to cool to room temperature.
11 -
Heat heavy cream and light corn syrup in a small saucepan until just boiling. Pour over chopped chocolate in a bowl, rest 30 seconds, then whisk until smooth. Cool to a pourable but thick consistency, whisking occasionally.
12 -
Place one cake layer on a serving plate. Evenly spread with one-third to one-half of the coconut-pecan frosting (depending on number of layers). Repeat, stacking the layers and spreading the frosting between. Finish with a layer of frosting on top. Drizzle the chocolate glaze over the top, letting it cascade down the sides. Slice to serve.