Shockingly, we ate at a place that wasn't a festival burger stand or our favourite cheap neighbourhood tapas bar, Bitácora, today.
On the recommendation of some friends, we visited a French bistro called El Casal, which hides away in the most touristy bit of El Barrio Gótico. The staff are French, there are lots of books everywhere and the place is a bit like what Shakespeare and Company might be like if they had a kitchen in the middle of the shop, There I ate the best salad I have had in a long while (not just because every molecule in me had been crying out for plants to eat) and everyone else ordered what they thought was tapas but came as a filling in massive hunks of bread.
They also do a day menu there which I want to try next time, which was several courses and cost about 10 Euros.
Go visit if you are in the busy part of town and need to refuel for cheap.