Two evenings a month an impressive form of dinner theater takes place in Greenport.That’s when Taylor Knapp, a young chef, commandeers the kitchen at Bruce’s Cheese Shop. Some might call the ensuing production a one-man show. Knapp calls it Pawpaw, a pop-up restaurant. The pawpaw tree, or asimina triloba, grows wild in the eastern United States. For just a few weeks each year, its branches bear a heavy globular fruit of the same name. For Knapp, the fruit’s fleeting appearance, and disappearance, is an apt metaphor for the essence of seasonal and locally-driven cookery. Virtually every ingredient on the changing nine-course menu, which costs $60--not including beverages, tax, or tip--has come from North Fork farms, nearby woods, and local waters.