CAKE: Pour boiling water over chocolate in small bowl; stir until melted. Set aside to cool. In large mixer bowl, cream butter and sugar until light and fluffy, add egg yolks 1 at a time, beat after each addition. On low speed beat in chocolate and sifted dry ingredients, beating whites.
Divide among 3 (8 or 23 cm) greased and floured cake pans or line greased pans with waxed paper. Bake at 180ºC or about 35 minutes. Frost with Coconut-Pecan Frosting.
ICING: Combine all but coconut and pecans in saucepan; cook and stir over medium heat until thick, about 10-12 minutes. Stir in coconut and pecans. Spread between and on top of cooled cake layers.