Preheat your oven to 350°F (175°C). Grease and flour three 9-inch round cake pans, lining the bottoms with parchment paper for easy removal.

In a large mixing bowl, cream together the softened butter and granulated sugar with an electric mixer until light and fluffy (about 3-5 minutes). Beat in the 4 egg yolks, one at a time, until well combined. Stir in the melted and cooled German's Sweet Chocolate until fully incorporated.

In a separate medium bowl, whisk together the all-purpose flour, baking soda, and salt. Gradually add the dry ingredients to the butter mixture, alternating with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined, being careful not to overmix. Stir in 1 teaspoon of vanilla extract.

In a clean, dry bowl, beat the 4 egg whites with an electric mixer until stiff peaks form. Gently fold the beaten egg whites into the chocolate batter in two additions until no streaks remain. This step is crucial for the cake's light texture.

Divide the batter evenly among the three prepared cake pans. Bake for 25-30 minutes, or until a wooden skewer inserted into the center comes out clean. Let the cakes cool in the pans for 10-15 minutes before inverting them onto wire racks to cool completely. Cooling completely is crucial before frosting.

In a medium saucepan, combine the evaporated milk, granulated sugar, butter cubes, and 3 egg yolks. Cook over medium-low heat, whisking constantly, until the mixture thickens to a custard-like consistency (about 10-12 minutes). Do not boil. The mixture should be thick enough to coat the back of a spoon.

Remove the saucepan from the heat. Stir in 1 teaspoon of vanilla extract, flaked coconut, and chopped pecans. Mix well to combine. Let the frosting cool completely to room temperature. It will thicken further as it cools.

Place the chopped dark chocolate in a small, heatproof bowl. In a small saucepan or microwave, heat the heavy cream until it just begins to simmer (do not boil). Pour the hot cream over the chopped chocolate and let it sit for 5 minutes. Whisk until smooth and glossy. Allow to cool slightly until it thickens enough to drizzle or spread easily, but is still pourable.

Once the cake layers are completely cool and the coconut-pecan frosting has thickened, level the cake layers with a serrated knife if necessary. Place one cake layer on your serving plate or cake stand.

Spread about one-third of the coconut-pecan frosting evenly over the first cake layer, leaving a small border. Carefully place the second cake layer on top and spread another one-third of the frosting. Top with the third cake layer and spread the remaining coconut-pecan frosting over the top of the cake, letting it cascade slightly over the edges.

If using the chocolate ganache, gently pour or spread it around the sides of the cake, allowing it to drip attractively. You can also drizzle some over the top of the coconut-pecan frosting if desired. Chill the cake for at least 30 minutes before serving to allow the frosting to set slightly.