Some of the city’s most serious food is being served in this tiny, tucked-away Tribeca restaurant. 

The place is definitely not a speakeasy – you’ve probably made your reservation far in advance, after all. Yet there’s apt to be some confusion when you arrive: Can a restaurant of this caliber really be ensconced behind a profusion of gaudy lighted doctors’ office marquees on a gray Tribeca block? Surely this can’t be the right door (it is).

Once inside, the proper woodsy pomp falls into place: a suited gentleman behind a tree-stump lectern verifies your reservation and leads you to your share of the 17 seats. You’ll sit either at the horseshoe shaped counter or a five-top table in back near the fragrant “living wall,” which is meant to perfume the air with herbal, vegetal notes (we detected none but were admittedly distracted by the food).

Should you be assigned a counter perch, you’ll be able to catch the action, or what there is of it, anyway: At times chefs seem to move so slowly and deliberately they could be working underwater. Meanwhile, as lighthearted music plays at a reasonable volume, you note the herb boxes strung across the frosted windows—which both make the restaurant that much more difficult to find and create the feeling of being tucked away, ensconced with fellow diners in the midst of some merry experiment.

The barman will snap you out of your trance: Would you like a cocktail? There’s no list, but he’s happy to announce the day’s offering aloud—on a recent visit these included a tangy rhubarb beer shrub and a winning Vesper variation bestowed with a single large ice cube. Then suddenly the “snacks” begin to arrive, a jaunty designation that belies the complexity of these largely delightful smaller bites that will make up the first third or so of your 20-some courses. With these playful starters, chef Matthew Lightner, who was the toast of Portland, Oregon, before decamping east to head up Atera artfully infuses a lightheartedness into his serious locavore sense of purpose.

“Don’t take me too seriously,” is the message of the first bite, a bar-menu riff fashioned from dehydrated sunchoke skins filled with strained yogurt and adorned with tiny, edible flowers, and presented (like many morsels here) and an upturned strip of tree bark. This initial playful offering – its taste and feel at once familiar and exotic – sets the tone for the meal. Many dishes follow. Some you will hold onto and some will get lost in the inevitable whoosh of memory that is all that remains after this kind of procession of meal (all the whooshier if you opt for the beverage pairing, which might match sake with one course, and bourbon with another).

If you’re lucky, the essence of at least one bite will chase you around. Maybe it’s a haunting recollection of how remarkably a snack called “razor clam” smacks of chowder cups from seaside childhood summers. Its curled mollusk-look-alike base has the stale crunch of a packaged oyster cracker, the creamy essence within (raw clam in clam mousse, as it happens) provides the buttery brininess of the soup itself.

Other courses delight in different ways: Foie gras “peanuts” are a ringer, texture- and color-wise, for the pillowy orange marshmallow version eaten by children — yet the taste is wholly adult. A curl of lichen-like substance presented on a slab of rock turns out to be edible and while its texture is that of a corn chip, its flavor is remarkably akin to … lichen.

At some point – most likely after an all-white dish of the freshest raw scallops available topped with dehydrated buttermilk shards and a sort of yuzu sorbet; and after a delicate salad of herbs and flowers laced with ruby-red folds of what you’re told is duck-tongue prosciutto – the chef himself might present you with a dish and ask you to identify it. You will fail at this. Something white and desiccated and chewy (dried squid, it turns out) is immersed in a confusing dark-brown deeply intense sauce that tastes of both the land and sea. And then there’s another element, so soft and buttery it has to be the pure pig’s fat known as lardo –it is. To Western eaters this distillation of roast pork juices and squid has no context – it’s a jumble of signs pointing different directions.

Yet that dish, which falls right in the middle, is the meal’s apex of mixed signals. Unlike some of the other well-known tasting-menu-style repasts, every element of surprise here is firmly rooted in what should be the priority: flavor. A sorbet that signals the beginning of dessert arrives as an airbrushed cookie “rock” – crack it open and the frozen stuff is inside. Another dessert resembles a block of charcoal; when your server whacks with a mallet it crumbles into the familiar taste of chocolate cookies over cream. And one more dessert looks exactly like a turning autumn leaf, and tastes like one too – a kind of sweet, sugared leaf you want to keep eating

Really, few courses are without some adornment of herbs of blossoms, which reflects Lightner’s obsession with local, wild foods. At times it seems as though a cadre of wood nymphs somewhere in back were in charge of the garnishing. In this way—with this elemental groundedness—the experience is more akin to entering the temple of one of the world’s finest sushi chefs than placing oneself in some modern-day culinary mad scientist’s hands. Come to think of it, that stack-up of medical signs out front is reminiscent of what you’ll encounter on the way to locating some of the finest tucked-away restaurants in Tokyo. There – and here – the discovery is more than worth it.

Atera, 77 Worth St. (Church St. and Broadway); 212-226-1444
Tasting menu, $150; optional beverage pairing, $90
Reservations required; book one month in advance