Francesinha literally means ‘little French (female person/thing)’. It’s a sandwich with meat and cheese, wrapped with more cheese, and then drenched in sauce… with a fried egg on top, served with fries. Associated with Porto, the city and region, you’d also find it in many other places in northern Portugal (and further south, but you’ll probably be laughed at). It’ll be available in fancy-ish restaurants through to simple cafes and bars that serve food.
Francesinhas are somewhat of a contentious topic because every northerner has a favourite place… it’s the best francesinha in the world whilst anywhere else serves the most disgusting bile. Any place that serves them will claim the same.
The meats in a traditional francesinha are usually sliced ham, a thin piece of beef, and sausage. The quality of these ingredients can vary; sometimes the beef is better and instead of plain hotdog mystery you’d get something that is more of a chorizo, like the one in the pictures.
The sauce is where the arguments are. It’s normally tomato-based with beer and varying degrees of spiciness. I’ve had some that were closer to tomato soup with no spiciness to ones where the beer is evident and quite spicy. The sauce has also migrated to other ‘fast’ foods… we’ve had burgerzinhas — it was as appalling (or appealing?) as you’d imagine — and as a hotdog bath. You can also buy it in jars for cooking at home.

For those not in the system, any variation would satisfy the experience of eating this uniquely-served sandwich. I wouldn’t fuss about finding the best one, although for those just visiting, Porto restaurants that specialise in them might be a good first sample; on the weekends you’d see these places packed with almost everyone eating francesinhas.
Here’s more of what one should know for when experiencing a francesinha. You may choose, or ask for, a half portion. The egg is always optional. You may ask for more sauce. Some restaurants may have additional variations on the classic, so ask for details to know how far from the original they are. Rarely, there are places that serve a vegetarian version, so if that’s your thing look out specifically for that in the menu ahead of time. We’ve seen a version without the sausage called ‘Jaquelina’, but I’m not sure how common that name is; in any case I would think that asking to leave some of the ingredients out would not be too much of a problem, but you might get a ‘look’. When asked, always say that it’s the best one you’ve had!
(Aos meus amigos portugueses, peço as mais sinceras desculpas por todos os erros horrÃveis que cometi neste post. Sou estrangeiro, por isso não me julguem com demasiada severidade! :D Por favor, corrijam-me nos comentários e declarem onde obter a melhor francesinha.)
Sooo many places to eat a good Francesinha, but right now, the best place is in Braga, a restaurant called "Casa Livita". You should go there! You MUST go there!