Preheat oven to 325 degrees F. Grease three 8-inch round cake pans. (Line with parchment paper if desired) Set aside. Separate eggs and beat egg whites to form still peaks. Put sugar, butter and shortening in mixing bowl and blend until fluffy. Add vanilla and yolks to batter and blend well. Add baking soda to buttermilk and let set for a few minutes (needs to be in a container larger than 1cup because it will foam). Add flour and buttermilk alternately into mixture until blended. Do not over beat. Add coconut and mix until incorporated into batter. Fold egg whites into batter. Pour batter into the three 8-inch cake pans, spread batter out evenly. Bake at 325 degrees for 25-30 minutes or until done. Cool in pans for 10 minutes and remove to wire rack to cool completely.