This is as authentic as it gets. Piles of rolls, pans of Muesa, fast service and not a tourist to be seen when we were there. You order from the counter, wait a few minutes as they prepare it, wrap it in wax paper then enjoy. There are a handful of plastic tables and chairs on the sidewalk where you plop yourself down and dig in. 1st don’t be intimidated it is really good. Tastes like a combo of mild liver and beef with a rich coating of juice…kind of like a burger. A range of texture from soft to chewy. The bread is soft and delicious ( maybe house made). Ordered 2 sandwiches ,a large Perone and a sparkling water €9 and we were full. Don’t forget to grab a piece of lemon to squeeze on the meat. It is a real experience and real treat. Give it a try!