Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x13 inch baking pan.
In a medium bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla.
In another bowl, sift together the flour and baking soda. Gradually stir the flour mixture into the creamed mixture alternately with the buttermilk, mixing just until incorporated. Fold in the chocolate chips, pecans, and coconut.
Pour batter into prepared pan. Bake in preheated oven for 30 to 35 minutes, or until a toothpick inserted into the center of the cake comes out clean.
To make the frosting, combine the evaporated milk, egg yolks, sugar, and butter in a medium saucepan. Cook over medium heat, stirring constantly, until the mixture thickens and coats the back of a spoon. Remove from heat and stir in the coconut and pecans. Spread over the cooled cake.
Interesting Facts
German Chocolate Cake is not actually from Germany.
The cake was named after the German-American chocolatier, Samuel German.
The traditional topping for the cake is a coconut-pecan frosting.