I found this restaurant by chance as I was wandering around Tunja looking for something to eat. I walked upstairs to find all the rooms completely jam-packed with locals. I told the staff I would return later, but they wedged me into a table with a local grandmother, who proved to be quite charming. When I jokingly said there were a lot of vegetarians in Tunja, she said, "No, just a few, but it's because the food is so delicious." There is no higher endorsement of a restaurant.
And indeed the food was delicious, starting with soup, then a big plate of brown rice and several prepared veggies and salad. Papaya juice and a small dessert rounded it out, for 7,000 COP. BTW, the woman's plate was smaller; she said she was having a "medio" (medium), so that's available for light eaters.
The set lunch was vegan, but I did see fried eggs going out on some plates, so it's not 100% vegan.