How to make
Put cocoa, sugar, butter and 70 ml (1/3 cup) of water in a small pot.
Once the mixture in the pot becomes homogeneous, remove it from the heat and separate 1 cup from it. In the rest add the flour, baking powder, eggs, vanilla and walnuts.
The new mixture is beaten with a mixer for 5 minutes. The prepared dough is placed in a greased baking pan (it is best to use baking paper).
Bake it for 20 minutes in a high heated oven.
After you take it out of the oven, while it is still hot, pour the leftover mixture over it.
If desired, you can add some finely chopped walnuts for decoration.
Leave it to cool completely.
