To prepare the dough, mix the yogurt, sugar, cocoa, oil, baking soda and flour well and pour it into a greased baking dish. Bake in the oven at 356°F (180 °C) for about 20-25 minutes.
Make a hot syrup made from the sugar, water, citric acid and essence. Pour it over the cooled and sliced cake. Make a cream from the butter, powdered sugar and yolks, then smear the cooled cake with the cream.