Step 1: In a large mixing bowl, combine the German chocolate cake mix, melted unsalted butter, water, and eggs. Mix with an electric mixer on low speed until just combined, then increase to medium and beat for 2 minutes until the batter is smooth. Scrape down the sides of the bowl as needed.
Step 2: Line a standard 12-cup muffin tin with paper liners or grease it thoroughly. Spoon the cupcake batter evenly into the prepared cups, filling each about two-thirds full.
Step 3: Bake in a preheated oven at 350°F (175°C) for 18-20 minutes, or until a wooden toothpick inserted into the center of a cupcake comes out clean. Remove from the oven and let them cool in the tin for a few minutes before transferring them to a wire rack to cool completely.
Step 4: While the cupcakes cool, prepare the Coconut Pecan Frosting. In a medium saucepan, combine the softened butter, shredded coconut, chopped pecans, evaporated milk, granulated sugar, egg yolks, and vanilla extract. Whisk everything together until well combined.
Step 5: Cook the frosting mixture over medium heat, stirring constantly with a whisk or heat-proof spatula. Continue to cook until the mixture thickens significantly, about 8-12 minutes. It should be thick enough to coat the back of a spoon. Remove from heat and let the frosting cool to room temperature, stirring occasionally.
Step 6: Once the cupcakes are completely cooled and the coconut-pecan frosting has reached room temperature (it will be thick and spreadable), use an offset spatula or knife to spread a generous amount of frosting over the top of each cupcake.
Step 7: If desired, garnish the frosted cupcakes with a dollop of whipped cream and a sprinkle of chocolate shavings. You can also add fresh berries or a small mint leaf for an extra touch of color and freshness. Serve immediately and enjoy your decadent creation!