Beat butter and shortening at medium speed with an electric mixer until fluffy; gradually add sugar, beating well. Add egg yolks, 1 at a time, beating until blended after each addition. Add vanilla and almond extracts; beat until blended.
Combine flour and baking soda; add to butter mixture alternately with buttermilk, beginning and ending with flour mixture. Beat at low speed until blended after each addition.
Beat egg whites until stiff peaks form; fold into batter.