Prepare the Cake:

1. Preheat and Prep: Preheat your oven to 350°F (175°C). Grease three 9-inch round cake pans with butter or non-stick spray, line the bottoms with parchment paper circles, then grease and flour the parchment. This ensures easy removal.
2. Melt the Chocolate: Place the chopped German’s Sweet Chocolate in a small heatproof bowl. Pour the boiling water over it and stir until completely melted and smooth. Set aside to cool slightly.
3. Combine Dry Ingredients: In a medium bowl, whisk together the flour, baking soda, and salt. Set aside.
4. Cream Butter and Sugar: In a large mixing bowl, using an electric mixer on medium-high speed, beat the softened butter and sugar together for 4-5 minutes until light, fluffy, and pale in color. This incorporates air for a tender cake.
5. Add Egg Yolks: Add the egg yolks one at a time, beating well after each addition. Scrape down the sides of the bowl as needed. Mix in the vanilla extract and the melted chocolate mixture until fully combined.
6. Alternate Dry and Wet: With the mixer on low speed, add the flour mixture in three additions, alternating with the buttermilk in two additions. Begin and end with the flour mixture. Mix just until combined after each addition—overmixing creates a tough cake.
7. Beat Egg Whites: In a separate clean, dry bowl, using clean beaters, beat the egg whites on high speed until stiff peaks form (3-4 minutes). The whites should stand up straight when you lift the beaters.
8. Fold in Egg Whites: Gently fold the beaten egg whites into the cake batter in three additions using a rubber spatula. Use a folding motion (cutting down through the center, across the bottom, and up the side) to maintain the airiness. Fold just until no white streaks remain.
9. Bake: Divide the batter evenly among the three prepared pans (about 2 cups of batter per pan). Smooth the tops with a spatula. Bake for 30-35 minutes, until a toothpick inserted in the center comes out clean or with just a few moist crumbs. The tops should spring back when lightly pressed.
10. Cool: Let the cakes cool in the pans on wire racks for 15 minutes. Run a knife around the edges, then invert onto the racks, remove the pans and parchment paper, and let cool completely before frosting (about 1 hour).

Make the Coconut-Pecan Frosting:

11. Combine Ingredients: In a medium saucepan, whisk together the evaporated milk, sugar, egg yolks, and butter.
12. Cook the Frosting: Place the saucepan over medium heat and cook, stirring constantly, for about 12-15 minutes. The mixture will thicken and turn a light caramel color. It should coat the back of a spoon. Don’t let it boil rapidly or the eggs will scramble.
13. Add Coconut and Pecans: Remove from heat and immediately stir in the vanilla extract, shredded coconut, and chopped pecans. Mix well to combine.
14. Cool the Frosting: Transfer to a bowl and let cool to room temperature, stirring occasionally. The frosting will thicken as it cools to a spreadable consistency (about 45 minutes to 1 hour). You can speed this up by placing the bowl over an ice bath and stirring frequently.

Assemble the Cake:

15. Layer the Cake: Place one cake layer on your serving plate. Spread about one-third of the cooled coconut-pecan frosting over the top, spreading it to the edges. Place the second cake layer on top and spread with another third of the frosting. Top with the final cake layer.
16. Frost the Top: Spread the remaining frosting over the top of the cake, leaving the sides exposed for that classic German chocolate cake look. The frosting naturally cascades down the sides slightly, which is perfect.
17. Serve: Let the cake sit for at least 30 minutes before slicing to allow the frosting to set. This cake is delicious at room temperature or slightly chilled.