I have frequented this restaurant numerous times and they are now completely gluten free apart from the blinis and the lasagna (which will be changed soon too I am told :).
The chef is lactose intolerant so has a very good understanding of what intolerance does.
All the sauces are outstanding and as mentioned glutenfree and they even have gluten free homemade bread.
The menu here is varied and you can everything from completely vegitarian to fish to excellent meatdishes.
There are very few glutenfree restaurants in the area (in Spain in general really) and El Sabor has a large glutenfree clientele as a consequence which means of course that they take pride in making everything as good as or even better than what would be "conventional cooking."
Apart from all this, the service is very good and I wholeheartedly recommend this restaurant.