Choco frito is Setúbal's signature dish — cuttlefish cut in strips, coated in flour and egg, deep-fried in olive or peanut oil, served with fries, lettuce, lemon and (usually) a side of bean rice. Simple, technical, hard to do well.
Casa Santiago on Av. Luísa Todi treats it as cathedral: counter seating, portraits of Bocage on the walls, queue at the door. O Farol, two minutes away, is the neighbourhood option. Others — O Miguel, Tasquinha do Mercado, Xico Setúbal — serve honest versions. Tip: go for lunch (these places serve 12:00–15:00 and most close at dinner); ask for a half portion if it's your first time.
The local cuttlefish is genuinely local: the Sado estuary and bay are its habitat, with daily landings at the fish market. Skip frozen choco — the good places only serve fresh.