Prepare the Cake:
Preheat your oven to 350°F (175°C) and prepare the German chocolate cake mix as directed on the box. Bake in a 9x13-inch pan until a toothpick inserted in the center comes out clean.
Poke the Cake:
While the cake is still warm, use the handle of a wooden spoon or a skewer to poke holes all over the cake, about 1 inch apart.
Add Sweetened Condensed Milk and Caramel:
Pour the sweetened condensed milk evenly over the cake, letting it soak into the holes. Then drizzle the caramel sauce on top, spreading it evenly. Allow the cake to cool completely.
Prepare the Coconut-Pecan Topping:
In a saucepan over medium heat, combine butter, evaporated milk, sugar, and egg yolks. Cook, stirring constantly, until the mixture thickens (about 10 minutes). Remove from heat and stir in vanilla, coconut, and pecans. Let it cool slightly.
Top the Cake:
Spread the coconut-pecan topping evenly over the cooled cake.
Optional Garnish:
Add a layer of whipped topping, drizzle with chocolate sauce, or sprinkle with chocolate shavings for extra decadence.