Melt chocolate in water and cool.
Cream butter and sugar. Beat in egg yolks. Stir in vanilla and chocolate.
Mix flour, soda and salt. beat in flour mixture, alternately with buttermilk.
Beat egg whites until stiff peaks form; fold into batter. Pour batter into three 9-inch layer pans, lined on bottoms with parchment paper.
Bake at 350° for 30 minutes or until cake springs back when lightly pressed in center. Cool 15 minutes; remove and cool on rack.
Filling and Topping
Beat egg yolks, milk and vanilla in large saucepan with wire whisk until well blended. Add sugar and butter; cook on medium heat 12 minutes or until thickened and golden brown, stirring constantly. Remove from heat.
Add coconut and pecans; mix well. Cool to room temperature and of desired spreading consistency.
Divide the filling evenly between the 3 cakes putting the 1st layer down. Then spread the filling evenly. Repeat with the other layer.