Cake: Preheat oven to 350 °F (175 degrees C). Grease and flour 3 - 9 inch round pans. Sift together the flour, baking soda and salt. Set aside. In a small saucepan, heat water and German chocolate until melted. Remove from heat and allow to cool. In a large bowl, cream butter and sugar until light and fluffy. Beat in egg yolks one at a time. Blend in the melted chocolate mixture and vanilla. Beat in the flour mixture alternately with the buttermilk, mixing just until incorporated. In a large mixing bowl, beat egg whites until stiff peaks form. Fold the whites into the batter until no streaks remain. Pour into 3 - 9 inch pans Bake in the preheated oven for 30 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow to cool for 10 minutes in the pan, then turn out onto wire rack.

Filling: In a large saucepan combine sugar, evaporated milk, butter, and egg yolks. Cook on medium heat 12 minutes or until thickened and golden brown, stirring constantly. Remove from heat. Stir in coconut, pecans, and vanilla. Cool to room temperature and of desired spreading consistency. Spread filling between layers and on top of cake.

Frosting: In a small saucepan, melt butter and semisweet chocolate. Stir until smooth and drizzle on top and down the sides of the cake.