I came up with my nature-preserve theory of tasting menus while eating a cabbage sandwich at Semilla, a new restaurant in Williamsburg, Brooklyn, across the street from Jack’s Cancellation Shoes and Rachel’s Corset Discount Center (“specializing in hard to fit sizes”).

Semilla had taken two cabbage leaves, then flattened and dried them until they were as crisp as a cracker. This was the bread. In between were a bundle of unusually delicious coleslaw and some grains of buckwheat groats. It wasn’t the most securely buckled-down sandwich I’ve ever eaten; some of the buckwheat fell out on the horseshoe-shaped counter around which Semilla’s 18 seats are arranged.

But I liked the way the buckwheat that stayed in the sandwich cracked between my teeth like Grape-Nuts. The flavors woke up old memories of the Polish and Ukrainian restaurants that are mostly gone from the East Village. And it was undeniably cool to have cabbage-leaf “bread” arrive at my place without warning. Diners at Semilla don’t see a list of the 10 or so courses for which they are being charged $75 until the next day, when an email arrives from the restaurant.

The sandwich struck me as a dish that might not last long on an à la carte menu. How many New Yorkers would choose to spend their dinner money on pressed cabbage when they could have broiled oysters or beef ribs or kale salad? By cordoning it off within a meal that has to be taken as a package deal, Semilla had sheltered the cabbage sandwich from the roughshod forces of the marketplace, the way the government might protect nests built by the gentle piping plover by banning four-wheel drive vehicles from the beach.