How to cook
Pour the egg and sugar into a bowl and stir with a wooden spoon for about 1 minute.
Add the yogurt and the soda, and stir to froth.
Separate a bit of the mixture into a teacup and add the cocoa.
Grease and flour a cake tin, pour the mixture, and color with the separate cocoa mixture.
Bake the cake at 356°F (180 degrees) for about 30-35 minutes.