Helvti Diner's burger concept is simple, and that's probably one of the reasons why it's so successful (this is its second location in town). You can customise your burger in three steps: first you choose the meat (Swiss premium, Angus, chicken or veggie), then your add-ons like bacon, cheese or fried eggs and then you decide on a sauce. Our burger was grilled medium and the meat was perfectly pink inside, just as we ordered it, but next time (and there will be a next time) we might order some guacamole for a little extra flavour. The service was quick and friendly.