Sift the flour and baking powder together in a bowl. Mix the eggs and sugar and beat at high speed with a mixer. After about 5 minutes of beating, add the oil little by little, while stirring constantly. Then add the vanilla and beat.
Finally, add the flour and baking powder spoon by spoon. Beat at least 10 minutes, until you get a yellow-orange mixture.
Then place 1/3 of the mixture in a separate bowl and then mix it with the cocoa. Pour the yellow mixture into a greased cake form. Add the brown mixture. Combine the two mixtures with a spoon.
Bake in a preheated oven, at 392°F (200 °C). Within half an hour, the cake should be risen and cracked. Pierce it with a toothpick or skewer and if nothing is stuck to it when pulled out, the cake is ready.
You can eat this cake instead of cozonac at Easter.