Melt the chocolate with boiling water; in large mixing bowl mix butter and sugar until light. Beat in eggs yolk, one at a time. Beat in chocolate and vanilla. Mix in flour, baking soda, and salt every other with buttermilk, beating after every addition until batter is sleek. Fold in egg whites.
Divide batter between pans until cooked.
Coconut-Pecan Frosting :
Mix sugar, milk, butter, vanilla, and egg yolks in a saucepan. Cook over heat, until thick, for 13 minutes.