I recommend Francesinha
A francesinha is a decadent Portuguese sandwich that originated in Porto. The sandwich is layered with thick white bread, wet-cured ham, smoked sausage (linguiça), and a grilled beef steak. The entire stack is completely covered with melted cheese and smothered in a rich, slightly spicy, beer-and-tomato-based sauce (called molho). It is typically topped with a fried egg and served with a generous portion of french fries meant to soak up the savory gravy.
Im from Portugal 🇵🇹 and francesinha tastes really good.
If some day you come to Portugal, I hope you will remember my suggestion.