1. Beat the eggs and sugar well. 2. Then mix yogurt and soda and add them to the mixture, soda. be careful of milk rise and may emerge from the glass:) 3. Add the oil. Finally, add the flour and vanilla, stirring constantly. 4. Brush cake form with oil and sprinkle with a little flour for the cake to get easier once it's ready. 5. Pour cocoa and stir until you get a solid brown color. 6. Bake for about 40-45 minutes in preheated oven at 180 degrees.