Preheat oven to 350°. Grease bottom and side of 3 (8- or 9-inch) cake pans. Line bottom of pans with round of wax paper.

Off heat, add chocolate to boiling water. Stir until chocolate melts. Allow to cool slightly.

Combine butter and sugar in a large bowl beating on high speed with an electric mixer until light and fluffy. Add egg yolks, one at a time, mixing well after each addition. Blend in chocolate and vanilla, mixing well.

Stir together flour, salt, and baking soda. Add to chocolate mixture, alternately with buttermilk, beginning and ending with dry ingredients. Beat until smooth.

Beat egg whites until stiff peaks form. Gently, blend about 1/4 of the chocolate batter into the egg whites. Then fold egg whites into the remaining batter. Blend gently until uniform color is achieved.

Divide batter evenly in prepared cake pans. Bake for 30 to 40 minutes or until a toothpick inserted in center comes out clean. Cool in pans on rack for 10 minutes, then turn out and cool completely on rack.

Frost with coconut pecan frosting.