Better-Than-Mom's German Chocolate Cake

1 . Stage

Preheat the oven to 350 degrees F (175 degrees C). Grease two 9-inch cake pans, line with parchment paper, and grease the parchment paper.

2 . Stage

Place semisweet chocolate, unsweetened chocolate, and water in the top of a double boiler over simmering water. Stir frequently, scraping down the sides with a rubber spatula to avoid scorching, until chocolate is melted, about 5 minutes.

3 . Stage

Beat 1 1/4 cups sugar and butter until light and fluffy, about 5 minutes. Beat in the melted chocolate. Add egg yolks, one at a time, mixing well after each addition.

4 . Stage

Combine flour, baking powder, baking soda, and salt in a bowl. Add 1/2 of the flour mixture to the creamed butter mixture and beat until well combined. Add buttermilk, vanilla extract, and the remaining flour mixture.

5 . Stage

Beat egg whites in a separate bowl until soft peaks form. Add 1/4 cup sugar and beat until stiff peaks form. Fold about 1/3 of the egg whites into the cake batter, then fold in the remaining egg whites, but do not overmix. Divide batter between the 2 prepared cake pans.

6 . Stage

Bake in the preheated oven until a toothpick inserted into the center comes out clean, 40 to 45 minutes. Cool for 10 minutes in the pans before inverting onto wire racks to cool completely.

7 . Stage

Prepare the filling while the cakes are cooling. Combine cream, sugar, and egg yolks in a medium saucepan and mix until well combined. Cook over medium heat, stirring constantly, until custard begins to thicken and an instant-read thermometer inserted into the center reads 170 degrees F (76 degrees C).

8 . Stage

Combine coconut, pecans, butter, and salt in a bowl. Pour hot custard over the pecan-coconut mixture and stir until butter is melted. Cool completely to room temperature.

9 . Stage

Make the syrup by heating water and sugar in a small saucepan over medium heat until sugar has dissolved. Remove from heat and stir in dark rum.

10 . Stage

Combine chopped chocolate, butter, and corn syrup in a bowl for the frosting. Heat cream in a saucepan until it just begins to boil. Remove from heat and pour into the bowl. Let stand for 1 minute, then stir until smooth and chocolate is melted. Cool to room temperature.

11 . Stage

Cut cake layers in half horizontally using a serrated bread knife. Set the first cake layer on a cake plate. Brush well with syrup. Spread 3/4 cup filling on top, making sure to reach all the way to the edges. Repeat with remaining cake layers, syrup, and filling, including the top.

12 . Stage

Frost the sides of the cake with chocolate frosting. Spoon remaining chocolate frosting into a piping bag and pipe a decorative border around the top and bottom of the cake.