I am not a vegetarian, but I strongly believe that they deserve to eat as well as non-vegetarians. This place was simply appalling.
We went into the restaurant and the lights were off, despite there being a paying customer already eating there. We asked the lady there (cook and waitress - the only staff member!) to turn the lights on and we got a menu. The menu is only in Spanish (not a problem for us, but it is meant to be a tourist friendly place).
We ordered a mixed salad to share, a pastel de quinoa for my girlfriend and a pastel de papas for me. The salad came out after about 15 minutes and was one of the worst salads I have ever eaten. It tasted dirty and none of the elements tasted as they should have. We sent it back.
After 40 minutes our pastels came out. The words flavourless and stodgy immediately come to mind. They were both heavy and tasted of very little. Mine also had undercooked potatoes in it.
In the end we had to argue in order for the salad to be taken off the bill and we left feeling highly dissatisfied. I felt a little sorry for the girl who was working there, as she was under too much pressure (doing everything), but really the whole experience was terrible.
Basically, serving bad vegetarian food is bad enough these days, but if you are a vegetarian restaurant it is inexcusable, especially when you are charging above standard prices for the city.