If you happen to be up north in Portugal, passing through Guimarães, there are two things you must do: spend an hour or so at the Paço dos Duques de Bragança, and eat at Restaurante Carreira.
It's one of those old-fashioned restaurants I just love where you walk through the kitchen to get to your table. I've only had one meal there, but everything we tried was outstanding. I suspect you really can't go wrong here... really about the best homestyle regional cooking I had in any restaurant in Portugal. It's the kind of place where most dishes come with a nice pot of arroz de feijão (rice cooked with kidney beans, and some bacon and chouriço, of course) on the side. Try anything that sounds good--it will be, I assure you. And it's the only restaurant I ever found that has doce de aletria on the menu--a traditional Portuguese dessert made with spaghetti-like noodles, the ubiquitous sweetened egg-custard, and cinnamon.....sort of like an eggy rice pudding, except with noodles. Sounds weird, but it's delicious. The place can be a bit tricky to find: it's out from the center of town--if memory serves, to the west--in the neighborhood called Silvares (there used to be a lot of car dealerships nearby). But ask around--it's worth the trouble! You also might want to call first...the last time I tried to go there it was closed, on a day when it was supposed to be open.
Rua 25 de Abril, 1
Silvares 4835-400 Guimarães, Portugal
(+351) 25 341 84 48