The enticing aromas of mussels marinière and tilapia dieppoise wafting up Vineyard Haven’s Main street beckoned several dozen customers into Le Roux on a recent Wednesday to witness master chef Jean Dupon, owner of Le Grenier, work his magic.

Once inside, customers jockeyed for any of the remaining seats arranged around the demo kitchen. Chef Dupon charmed his audience with stories of life in France, as he assembled his mis en place. On the counter sat carafes of wine, heavy cream and butter, awaiting his generous hand. Anticipating health-conscious concerns, Mr. Dupon appeased the crowd with declarations that he only uses “skinny cow butter.” Phew. Two full carafes of chablis also raised a few eyebrows, but not for long, as the old-school chef reminded the sober crowd that “We live happily in France.”

Chef Dupon had all burners and ovens fired, masterfully transforming simple, fresh ingredients into heavenly dishes with depths of flavor, all the while explaining his techniques and cooking philosophies. “Reduce! Reduce! Reduce!” he advised. As each dish came together, the rapt audience watched intently. Mr. Dupon deftly spooned up samples to the swooning crowd. Each successive dish was declared a pièce derésistance, with customers unabashedly drinking the last drops of sauce out of their bowls, pronouncing it “utterly divine.”

Le Roux’s popular cooking demonstrations have proven so successful that owners April and Michael Levandowski are considering adding alternative day and evening demonstrations to accommodate the expressed interests of both the demo chefs and eager patrons. Future demonstrations include Blue Canoe chef Nicholas Wilson sharing his fine dining expertise on May 5 and Armen Hanjian working with Armenian pastry on May 12.

After sampling dishes created by Island chefs and home cooks in Le Roux’s well-equipped demo kitchen, customers are offered generous coupon incentives to browse for bargains. Inspired by Chef Dupon’s mussel work, patrons strolled Le Roux’s aisles looking for the precise pans, kitchen tools and specialty ingredients necessary to create their own culinary delights at home. Others, perhaps requiring further inspiration, decided upon reservations . . . at Le Grenier.