I've never been in this "restaurant". But I love it.
A long, long time ago, I was wandering in Gerez with my family, by lunchtime, and, not knowing the area, we decided to search a restaurant in Portela do Homem. Silly idea. It was only a customs barrier, away from it all, with Spanish forest in face. I asked to one of the guards where in the area could we eat, and he had a very Portuguese answer:
"If you want my sausage and bread, help yourselves, but restaurants, in this area... none. Not in Portugal nor in Spain."
Now, we are in EU, the frontier is gone, and the police installations became a... restaurant.
You may rely on something more than sausage, and for sure, the same kindness I found there.
- National/State Park
If you are hiking in the National Park or just enjoy this kind of activity, you will find some places inside the Park proper to have meals. Those places are equipped with benches and tables and I think that in some cases they have proper places to lit fire. And pack everything you might need for your meals before you go, as you won't find any seller here, not even for a bottle of water.