The neighborhood Italian restaurant is a highly formulaic institution. Different regional influences add some variety, but the basics remain steady. That’s why Spiga, a new Upper West Side restaurant that brings avant garde ideas to the neighborhood Italian table, is exciting – at least in theory.

The wood-lined space looks innocuous, but the chef, Salvatore Corea, has a knack for turning familiar dishes in novel directions. He adds cocoa to his gnocchi and radicchio to his dessert, and imprisons mussels in gelatin. The ultimate effect is varied: Some of the experiments yield delightful results, while others simply mystify. Most lie somewhere in between.

The cold “seafood pudding” ($10.95), in which chewy mussels and firm pieces of fish are encased in a gelatin mold, closely approximates the seafood’s murky, chilly natural habitat. The experience is well outside the usual comfort zone, but somehow leaves one craving more. A triple treatment of cod ($12.95) is a little more accessible. It comprises strips of toothsome cod carpaccio, drizzled with olive oil and offset by a refreshingly earthy bean puree; a fluffy dollop of whipped salt cod, classic as you could desire; and a golden little piece of fried cod that’s given an odd dimension by a jarring dab of bitter lemon marmalade.

Another starter spices up a blob of ultra-creamy burrata cheese with a scoop of fiery red-pepper jelly ($12.95). The complex fruitiness and heat of the pepper sit beautifully against the burrata’s cool, rich simplicity. In comparison, the restaurant’s beef tartare ($13.95) is fairly traditional, its meat’s salty tang enhanced by crisp layered wafers of parmesan.

The cocoa-laced gnocchi ($17.95) is the most attention-grabbing of the pastas. It took a moment to piece together where I’d had this evocative combination of warm chocolate flavor and pillowy texture before. Something wintery … yes! Hot cocoa with marshmallows! Except I’ve never had boar in my cocoa. Here, the strong bittersweet flavor of the chocolate, in combination with a dark sauce of boar shreds and mushroom pieces, adds up to a heaviness that runs counter to the spirit of gnocchi. A bite or two of this dish is intriguing, but a whole plate of it can be hard to take.

When the kitchen plays its hand straight, the results may be less eye-opening but are often more satisfying. Such is the case with a dome of soft, ribbony tagliolini ($15.95), dotted with pieces of mullet fish and plump macerated berries, and surrounded by a light tomato sauce with a fennely tinge. The treatment of delicate garganelli ($14.95) is even less challenging: well-cooked broccoli pieces, tender nubs of pork, and a buttery sauce.

Main courses, for the most part, occupy a different tier: They are substantial, minimally distorted pieces of meat or fish that demand no leaps of faith on the part of the eater. Pork loin ($21.95) is sauced with a spiced honey reduction and perked up with pieces of soppressata. The loin itself is a winner, large and unusually juicy. The dish’s one avant-garde touch is a ball of “fried cream,” a puffy, bland pastry object that I needed help to finish. Salt-crusted sea bream ($20.95) arrives in the form of a glistening golden slab. Disappointingly, that slab is just the salt crust, which must be cracked and removed, but the fish it reveals is succulent and only subtly salty. Cheesy fried eggplant rounds give the simple dish additional grounding. Chocolate-sauced duck breast ($24.95) sounds like it’ll be another experimental one, but the chocolate just enriches the succulent, familiar duck and barely shows its own personality at all.

The kitchen seems to have used up much of its allowance of sweetness in the savory courses, leaving several of the desserts (all $8.95) to rely on vegetables or other unconventional, off-sweet flavors. In some cases this works, as with a light and refreshing fennel sorbet whose mellow iciness is set off by appealing, crisp-tender slices of mango and celery. But an unfortunately dense white-chocolate souffle is dragged down by the unlikely companionship of bitter radicchio leaves. How this pairing is intended to work is unclear; even to an open-minded tongue, the disharmony is grating. Chocolate-licorice semifreddo has potential, but its balance is poor, leading with a pungent licorice wallop that doesn’t allow the chocolate to get much of a footing.

A fine selection of Italian dessert wines offers a more conventionally satisfying closure to the meal: A Malvasia delle Lipari ($12) has a lingering sweetness and a keen density reminiscent of dried fruit; a botrytized verdicchio ($14) balances honey with tart fruit. Seventy Italian wines, eight of which can be ordered by the glass, comprise the main list. A morellino di Scansano from Marteto has a juicy, sturdy simplicity that makes it a good companion for exploring the menu’s wilder regions.

The surprises that Spiga holds in store for the unsuspecting palate make it notably unusual. Whether that is a good or bad thing, the neighborhood will decide.

Spiga, 200 W. 84th St., between Amsterdam Avenue and Broadway, 212-362-5506.