1Preheat oven for 350 degrees. Prepare 3 - 9 inch cake pans with flour and shortening, place to side.
2Cream butter until soft and fluffy, add sugar. Cream mixture for about 6 minutes or until well incorporated. Add eggs, one at a time, mixing thoroughly after each addition. Add flours and buttermilk alternately, beginning and ending with flour. Add vanilla and beat well.
3Divide batter between the 3 pans, baking for about 25 to 30 minutes or until toothpick inserted in middle comes out clean.
4Let cool in pans for about 5 minutes before turning them out onto cooling racks. Allow to cool completely.
Mix all ingredients in a 4 qt pot. Stir ingredient constantly, to keep from scorching. Cook to soft stage(230-240 using a candy thermometer. Remove from heat and beat icing with a wooden spoon until creamy. Spread on cool cake.