"Um galão por favor".
This is how you ask for a latte in Portuguese. And at this place, they make a delicious one. They also sell portuguese pastries (OH MY GOD CUSTARD TARTS), cheese and meats.
Ask for a latte, a sandwich (grilled ham and cheese is my favourite), and a dessert for a full portuguese bakery experience.
I suggest trying all kinds of tarts so you can find your favourite.