Step 1: Preheat your oven to 350°F (175°C). Grease and lightly flour three 9-inch round cake pans.
Step 2: In a large mixing bowl, cream together the softened unsalted butter and granulated sugar until the mixture is light and fluffy, about 3-4 minutes.
Step 3: Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. Stir in the vanilla extract until well combined.
Step 4: In a separate medium bowl, whisk together the dry ingredients: all-purpose flour, unsweetened cocoa powder, baking soda, baking powder, and salt.
Step 5: Gradually add the dry ingredient mixture to the wet ingredients, alternating with the buttermilk. Begin and end with the dry ingredients, mixing just until no streaks of flour remain. Be careful not to overmix.
Step 6: Divide the prepared cake batter evenly among your three greased and floured cake pans.
Step 7: Bake in the preheated oven for 25-30 minutes, or until a wooden skewer or toothpick inserted into the center of a cake comes out clean.
Step 8: Allow the cakes to cool in their pans for about 10 minutes before carefully inverting them onto wire racks to cool completely.
Step 9: In a medium-sized saucepan, combine the granulated sugar, evaporated milk, unsalted butter, and egg yolks. Cook this mixture over medium heat, stirring constantly, until it thickens and gently boils, which usually takes about 10 minutes.
Step 10: Remove the saucepan from the heat and stir in the vanilla extract, sweetened shredded coconut, and chopped pecans. Allow the frosting to cool to room temperature; it will continue to thicken as it cools.
Step 11: Once your cake layers are completely cool, place one layer on your preferred serving plate or cake stand. Spread a generous amount of the coconut pecan frosting evenly over the top.
Step 12: Carefully place the second cake layer on top and repeat the frosting process. Add the final cake layer and spread the remaining frosting over the top and sides of the cake, ensuring an even and appealing coating.
Step 13: Your homemade German Chocolate Cake is now ready to be proudly sliced and served!