Heat oven to 350º line bottoms of 3 (9-inch) round pans with wax paper. Unless you use nonstick pans.
Microwave chocolate and water in a large microwave bowl on high 1 1/2 to 2 minutes or until chocolate is almost melted, stirring halfway through heating time. Stir until Chocolate is completely melted.
Mix flour, baking soda and Salt; set aside. Beat butter and sugar in large mixing bowl with mixer on medium speed until light and fluffy. Add egg yolks, 1 at a time, beating well after each addition. Stir in chocolate mixture and vanilla. Add flour mixture alternately with Buttermilk, beating after each addition until smooth.
Beat egg whites in another large bowl with electric mixer on high speed until stiff peaks form. Gently stir into batter. Pour into prepared pans. Bake 30 minutes or until Cake springs back when lightly touched in center. Immediately run spatula between cakes and sides of pans. Cool 15 minutes, remove from pans. Remove wax paper. Cool completely on wire racks.
Spread Coconut-Pecan Frosting between layers and over top of cake.
Filling or Frosting
Mix milk, sugar ,butter, egg yolks, and vanilla in large saucepan.
Cook and stir on medium heat about 12 minutes or until thickened and golden brown. Remove from heat.
Stir in coconut and pecans. Cool to room temperature and of spreading consistency.
Top of stove preparation: Heat chocolate and water in heavy 1-quart saucepan on very low heat, stirring constantly until chocolate is melted and mixture is smooth. Remove from heat. Continue as above