Separate eggs; place all the whites in a large bowl, place 3 yolks in one small container, and the other 3 in another. Prepare 3 8-inch cake pans with brown-paper rounds (for bottoms) greased with shortening. Preheat oven to 350 degrees F. Soften 1/2 C butter in a large bowl; add confectioner's sugar and beat until thoroughly mixed. Add 3 egg yolks, one after another, and continue beating. Add vanilla and mix till thoroughly blended, scraping sides with spatula if necessary. Measure flour into a small bowl and stir in baking soda. Add to butter/sugar mixture alternately with buttermilk in 4 steps, beginning and ending with the flour. Sprinkle about 1/2 t salt on egg whites. Beat till stiff, but not dry. Fold egg whites into batter. Divide batter between pans and bake at 350 degrees F. about 30-35 minutes, until done. TOPPING: Put 1 stick butter in pot; add sugar and cream. Bring to rolling boil over medium heat for a few minutes and cool. Add confectioner's sugar until you have the right consistency. When cakes are done and cooled, put together with cooled topping.