Cream butter, gradually add sugar, beating well. Add egg yolks, one at a time, beating well after each addition. Dissolve soda in buttermilk and add to batter alternately with flour, beginning and ending with flour. Stir in bananas.
Beat egg whites until stiff peaks form, and fold into batter. Pour batter into two greased and floured 8-inch cake pans. Bake at 350 for 30 minutes or until cake tests done. Cool cake in pans for 10 minutes; remove layers from pans, and let cool completely. Fill layers and frost with banana pecan or caramel frosting. The banana pecan frosting is Grandma Spoor’s recipe; the caramel frosting is from The Southern Heritage Cakes Cookbook.