If the Duck Soup here (small 800, medium 1000, large 1500 HUF) doesn't sort you out, then consult a medical professional. Though situated on Nagymező, the so-called Broadway of Budapest, not tucked away on some back alley, the customers that file in surreptitiously, all act as if they've stumbled onto some El Dorado, which in a way they have. 55 different dishes using fresh ingredients and real Vietnamese street food recipes. The décor is as cheerful as tinsel on a Christmas tree and service is brisk without being pushy.