Cream butter and sugar. Beat in egg yolks. Add vanilla and salt. Add white chocolate that has been melted in top of double boiler or (slowly and carefully) in microwave. Mix well. Add baking powder and stir in flour alternately with buttermilk. Beat 4 egg whites and fold into mixture, along with pecans and coconut. The batter can be baked in a greased and floured tube pan or a 9 x 13-inch pan or in 2 large and 5 small loaf pans. For a large cake, bake at 350° for 45 minutes.