The lobby of the Hilton Diagonal Mar Hotel is not where you would expect to find a restaurant serving progressive cuisine. The unusual space, where diners are grouped together around two counters, won the award for the best restaurant design in Europe in 2019. The chef, Artur Martínez (formerly of Capritx,) crafts a Modern Mediterranean menu that favors minimalist preparations: a single leek that sits next to a dab of ginger mayonnaise; Mediterranean green curry made from herbs, spices, vegetables and local fish; and a thick slice of duck that has been smoked and is paired with turnips.