On a sunny November afternoon, New Yorkers stroll in parks and along riversides. Members of the The Collective gather at Pier A Harbor House. Sean McClure, head bartender at Sweet Polly, is leading a workshop in improving the garnish game. Angel’s Envy provides spirits for cocktails and tools for participants: notebooks, cutting boards and ceramic paring knives. Side tables bear glasses of edger scissors, fresh edible flowers, fruit, vegetables and paper-thin slices of dehydrated pineapple.