Melt chocolate in boiling water. Cool. Cream butter and sugar until fluffy. Add yolks 1 at a time, beating well after each. Blend in vanilla and chocolate. Sift flour with soda and salt;add alternately with buttermilk to chocolate mixture, beating after each addition until smooth. Fold in beaten whites. Pour into three 23 cm layer pans, lined on bottoms with paper. Bake at 180ºC or 30 to 35 minutes. Cool. Frost tops only. For COCONUT-PECAN FROSTING. Combine 1 cup evaporated milk, 1 cup sugar, 3 slightly beaten egg yolks, half cup butter and 1 teaspoon vanilla. Cook and stir over medium heat until thickened, about dozen minutes. Add 1.3333333333333 cups ANGEL FLAKE coconut and 1 cup chopped pecans. Cool until thick enough to spread, beating occasionally. Makes 2.5 cups.