German Chocolate cake

I got the recipe from a professional baker

German Chocolate CakeIngredients: 

1 package (4 ounces) German sweet chocolate1/2 cup water

4oz. semi sweet chocolate

o 1 cup butter, softened

o 2 cups sugar

o 4 eggs, separated

o 1 teaspoon vanilla extract

o 2-1/2 cups cake flour

o 1 teaspoon baking soda

o 1/2 teaspoon salt

o 1 cup buttermilk

o FROSTING:

o 1 cup sugar

o 1 cup evaporated milk

o 1/2 cup butter

o 3 egg yolks, beaten

o 1-1/3 cups flaked coconut

o 1 cup chopped pecans

o 1 teaspoon vanilla extract

o ICING:

o 1/2 teaspoon shortening

o 1 square (1 ounce) semisweet chocolate

Directions: 

Line three greased 9-in. round baking pans with waxed paper. Grease waxed paper and set aside. In small saucepan, melt chocolate with water over low heat; cool. 

In a large bowl, cream butter and sugar until light and fluffy. Beat in 4 egg yolks, one at a time, beating well after each addition. Blend in melted chocolate and vanilla. Combine the flour, baking soda and salt; add to the creamed mixture alternately with buttermilk, beating well after each addition. 

In a small bowl and with clean beaters, beat the 4 egg whites until stiff peaks form. Fold a fourth of the egg whites into the creamed mixture; fold in remaining whites. 

Pour batter into prepared pans. Bake at 350° for 30 minutes, or until toothpick inserted near the center comes out clean. Cool for 10 minutes before removing from pans to wire racks to cool completely. 

For frosting, in a small saucepan, heat the sugar, milk, butter and egg yolks over medium-low heat until mixture is thickened and golden brown, stirring constantly. Remove from the heat. Stir in the coconut, pecans and vanilla extract. Cool until thick enough to spread. Spread a third of the frosting over each cake layer and stack the layers. Melt chocolate with shortening, stirring until smooth; drizzle down sides of cake.