Preheat oven to 350 degrees F (175 degrees C). Grease and flour 3 (9 inch) pans. Sift together the flour, baking powder and salt. Set aside.
In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the yolks one at a time, then stir in the melted chocolate and vanilla. Beat in the flour mixture alternately with the buttermilk. Stir in the nuts and coconut.
In a large glass or metal mixing bowl, beat egg whites until stiff peaks form. Fold 1/3 of the whites into the batter, then quickly fold in remaining whites until no streaks remain. Divide batter into prepared pans.
Bake in the preheated oven for 40 to 45 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow to cool.