Forget the cheesesteak debates. Porto has quietly built a reputation as one of the world's great sandwich cities, thanks in large part to one gloriously over-the-top creation: the francesinha. Named the standout of the city's food scene in a recent Daily Passport feature, this isn't a light lunch — it's layers of bread and meat buried under melted cheese, sometimes crowned with a fried egg, then drowned in a tomato and beer gravy you'll want to mop up with fries. Think croque monsieur, but with Portuguese generosity and a lot more meat.

The dish is usually credited to Daniel David da Silva, a cook who picked up ideas during his time in France and reworked them for local tastes. Today every kitchen has its own take. Café Santiago does a meat-lovers' build of ham, sausage and steak under the Pereira family's secret sauce, a short walk from one of Rick Steves' favourite markets. Vegetarians are catered for at Lado B, which swaps in tofu, soy sausage and eggplant, while Capa na Baixa turns up the heat with a spicier gravy.

But the francesinha is only the start. The cachorrinho is a thin, pressed sausage-and-cheese sandwich brushed with piri-piri — a chilli, garlic, lemon and bay leaf paste — best eaten at Gazela, a beer hall running since 1962 and a 15-minute walk from the Ribeira district. Casa Guedes has been piling warm bread with thin slices of roasted pork leg (add the sheep's milk cheese) since brothers Manuel and César Correia opened in 1987; pair it with a stroll through the nearby São Lázaro Garden, the city's oldest public green space. And the bifana, pork simmered tender in beer, garlic, chilli, bay and white wine, has its shrine at Conga, a fixture on Bonjardim Street since 1976.

What makes Porto different from other sandwich destinations is the setting. The city sits where the Douro River meets the Atlantic, so lunch comes with port wine lodges, pastel facades and the coastal Pérgola da Foz boardwalk. Grab your sandwich to go and eat it by the water.

For travellers, this is an affordable, walkable food trip that doesn't require reservations or fine-dining budgets — just an appetite and comfortable shoes.