How to cook
Stir the egg, sugar, oil and cocoa well. Add the baking soda to the yoghurt. Once it swells, add it to the egg mixture.
Add the flour in small lots and stir to prevent lumps. Bake in a form with removable sides at 320°F (160 °C) until your toothpick comes out dry when you poke it.
Leave the baked cake to cool completely. Cut it into 8 identical pieces. Make the glaze from the listed ingredients.
Put it on the stove and once the butter and sugar melt, take it off. Smear it on the cake with a brush. Finally, sprinkle with ground walnuts.