Polish open-face sandwiches (also known as French-bread pizzas) are popular street food in the bigger cities of Poland. They're known as zapiekanki (plural) or zapiekanka, which is singular. Zapiekanka comes from zapiekac, which means "to bake," and is the culinary term for a casserole. Most zapiekanki sandwiches start with French bread, sauteed mushrooms, cheese and ketchup, but there are Hawaiian-style zapiekanki with pineapple, and Greek style with olives and feta cheese. Of course, the beverage of choice with a zapiekanka is Polish piwo (beer)!