Cream butter and sugar, add egg yolks, vanilla and beat well.
In separate bowl - the flour, baking soda and baking powder using a whisk to mix).
Add the dry ingredients alternately with the buttermilk/poppy mix.
Beat eggs, fold in the stiffly beaten egg whites
In a greased angel food pan (I use a bundt pan) spread batter in layers sprinkling each layer with the sugar/cocoa/cinnamon mix and swirl with a knife.
Bake one hour at 350 degrees or until toothpick come out clean.