Separate the whites from the yolks, add 1 cup sugar to the whites, the oil to the yolks.
Beat both mixtures with a mixer, then mix them together and add the flour.
Set aside a little of the prepared mixture, add the cocoa to it.
Smear the cake form with a little oil and flour and pour in a little of the cocoa mixture, a little of the rest and so on until you've run out of mixture.
Bake at 374°F (190 °C) until ready. Sprinkle the ready cake with powdered sugar, which you've mixed with a little cocoa, or just with powdered sugar and chocolate spread.
Decorate as desired.