The people of Portugal love a sandwich, and one of the country’s most beloved is the bifana. Taking the form of slices of pork served in a roll, in Lisbon that protein is typically grilled, but somewhat confusingly, the city’s most popular bifana is done in the northern style. You don’t need Google Maps to know if you’ve arrived at As Bifanas do Afonso; look for the perpetual line or simply follow the aroma of porky broth that extends down the block. Your destination is essentially a stall, which specializes…