Dibaka is a very nice restaurant the center of Sofia. The food and service is good. It's packed on weekends, but you can not book in advance. We ate like kings, we each had a beer and a bottle of wine between two, appetizer and main course, it was 10 euros per person! It was very cheap because it was a nice place and wasn't like a normal dive. There is a nice terrace outside, with greenery, then a part under a veranda, which is for smokers and not very well ventilated, but if smoke bothers you then there is a smaller room that is not smoking. Bulgaria is a country where people smoke a lot. I tried a soup served in a bread roll, so you eat the bread and soup at the same time.