Instructions
Heat oven to 350 degrees F. Grease 2 9-inch square pans or 3 8-inch round pans.
Pour boiling water over chocolate, stirring until chocolate is melted; cool. Mix sugar and butter in large bowl until light and fluffy. Beat in egg yolk, one at a time. Beat in chocolate and vanilla on low speed.
Beat in flour, baking soda and salt alternately with buttermilk, beating after each addition until smooth. Fold in egg whites.
Divide batter among pans. Bake square pans for 40 to 45 minutes or round pans for 35 to 40 minutes. Check for doneness with a toothpick in the center. Cool and top with coconut-pecan glaze.
Coconut-Pecan Glaze: Combine sugar, butter, milk, vanilla and egg yolks in a saucepan. Cook over medium heat, stirring occasionally, until thickened, about 12 minutes. Remove from heat. Stir in coconut and pecans. Beat until spreadable. Cool and thicken before frosting cake.
