Lunch at Casa Guedes is one of our favorite culinary rituals in Porto: After snagging a seat at the bar during the midday rush, we sit, mesmerized, as Mr. Cesar nimbly cuts slices of roasted pork shank, then places them on bread and moistens it all with his secret sauce. While not the only item on the menu, the famous sande de pernil (roast pork sandwich) is Casa Guedes’s raison d’être. After taking in Mr. Cesar’s entrancing sandwich-making choreography, we order the upgraded version of the sande, which is topped with gooey queijo Serra da Estrela, a creamy sheep’s milk cheese. Seating at this humble and low-cost eatery used to be minimal, and Casa Guedes’s popularity had long outstripped its capacity – fans could be found waiting patiently in queues stretching down the block.

A gloppy, meaty, cheesy brick served in a pool of sauce and with a mountain of fries: please meet the francesinha, the culinary pride and joy of the city of Porto. Today, restaurant billboards proclaim in many languages that they serve the best version in the world, revealing the genuine power of this artery-clogging combination that, incredibly, was originally conceived as a snack. We have to say it though: eating a francesinha is worth every last calorie. This dense sandwich, which is impossible to eat just with your hands, is often considered the lusophone version of the croque monsieur.

The sensation of entering A Cozinha do Manel (“Manel’s Kitchen”) in Porto is so similar to entering grandma’s house on Sunday that it almost confuses us. There is no one to greet you at the door, no cloth napkins folded over employees’ arms. We walk confidently, as we would at home, with the sense of comfort that only intimacy is capable of inspiring. From the wall, among the many clocks, vintage plates and drawings made on cloth napkins by customers with an artistic bent, dozens of familiar faces look back at us. They are actors, musicians, politicians and soccer stars all standing next to Zé António, the owner and manager – a confirmation of the restaurant’s popularity.