How to make
Mix the flour, sugar, baking soda, salt and cocoa in a dry bowl. Add the oil, water and vinegar.
Knead it well and place in a greased oven dish. Bake in a moderate oven about 20-25 min.
In the meantime, prepare the glaze.
Put the ingredients for it in a pan and stir until the butter melts and you get a medium dense mixture.
Poke holes in the ready layer with a match and smear it with the glaze.