This was given to me by a very good Bulgarian friend, Nadejda Loumbeva, who translated it from her mother's private recipe. I converted it to vegan as an experiment, and it worked surprisingly well (very well). Quantities are approximate from memory: take them with a pinch of salt, use plenty of fruit and nuts, and let me know if you have suggested changes.
The biggest problem I had was with the cake collapsing while being baked, losing all the air. I haven't solved it completely. All I can recommend is to bake for as long as you dare before opening the oven, to give the cake maximum chance to set before you disturb it by opening the oven. If you know how to fix this, please share!