The gold standard for creamy clam chowder is the bowl at Artistry on the Green, in the Inn at Hastings Park in Lexington. Chef Mathew Molloy makes his chowder with quahogs, big bivalves that he steams in white wine just until they open. He strains and reserves the intensely clammy liquor to make the stock, to which he adds mostly heavy cream and half-and-half. The clams are chilled, and the meat chopped. Molloy cooks onions slowly in the fat from his own house-cured salt pork to add a smoky element. The bowls are garnished with chopped fresh chives.