Crustaceans Go Global

flex mussels is doing something right. this prince edward island offshoot seems to have no trouble packing the small, almost subterranean, space each night with crustacean-loving locals, despite being tucked away on a dark and often construction-ridden 82nd street, too far off third avenue to attract foot traffic. and what this "something" is, of course, is mussels.

what you'll notice about the cavernous and narrow interior is actually the hunched backs and hidden faces of rapacious patrons diving head first into massive metal pots. while the décor-soothing earth tones and lush shots of the signature canadian island-is certainly pleasant enough, it's the mussels that are drawing the crowd.

all mussels at flex hail from the restaurant's p.e.i. birthplace. there are as many variations and preparations of the seafood here as there are of cupcakes at crumbs. what flex has gotten so very right is knowing what it does well and sticking to it. this is certainly not the first restaurant to tout the mussels and fries routine. belgium has more of a claim on that stint than canada for sure. but flex does exactly what its very clever name suggests: it flexes the usual concept of this classic dish without drowning the main ingredient in self-serving experimentation or so-called creativity.

and what better way to break monotony than with a sexy geisha (sake, green onions, pickled ginger, garlic, birds eye peppers), a strong spaniard (chorizo, sweet peppers, spanish olives, red wine, tomatoes) or perhaps even a simple spartan (kalamata olive, garlic, tomato, oregano, olive oil)? if you're feeling particularly randy, go for some brandy, with the bisque (lobster, brandy, tomato, garlic, cream). if you're of the prudish variety and prefer conventional fare, look to the aptly named abbey (belgian triple, caramelized onions, orange zest). one of my favorites is the rather indulgent maine (lobster, smoked bacon, corn, white chowder, parsley), as the corn, chowder and bacon meld together to create a layer of rich sweetness that coats the meaty mussel and plush lobster bits.

mussel dishes range in price from $16 to $20. considering the giant metal pot, comprising a heaping steaming pound of mussels, plus complimentary bread with which to mop up the savory broth, $20 is not bad for a full meal in new york city, let alone the upper east side. you will most definitely want to get an order of the flex famous hand-cut fries to use as another broth consumption utensil. the fries are cut thin, but still meaty, and are perfectly crisp and salty. if you are looking to keep your meal on the cheap side, skip the appetizers. generally overpriced for what they are, and not particularly noteworthy anyway, you will most likely be glad you did. salads range from $12 to $14, which is rather expensive given the slivers of prosciutto that accompanies the spicy greens or the few bits of bacon atop the iceberg wedge. the burnt fingers, fried calamari, shrimp, oysters, shallot rings, with a spicy aioli, would be worth trying if they weren't priced at $16, as much as a full entrée. same goes for the crab cake, plump with maryland crab in a rather refreshing citrus aioli at $17.

there is another section of the menu called "not mussels" that is considerably less focused and cohesive in theme, execution and price. these alternative entrees include a few seafood dishes and a roasted chicken breast. that's right, a chicken dish, just one. no red meat to speak of. prices of these entrees pick up where the mussels left off, starting at $21 and reaching to $27. the lowly chicken will put you back a good $25. so, unless you are allergic, my advice is to stick with the mussels or dine elsewhere.

desserts are quite pleasant in their simplicity. some are also a bit of a throwback, like the strawberry shortcake or the chocolate and cream cheese version of the classic whoopee pie, both of which serve as a rather fitting finale to a simple and satisfying quintessentially northeastern meal.

flex has a considerable and thoughtful wine list organized by flavor profile, with many bottles under $50. the canadian selection on the beer list is esoteric but appreciated and complements beers from the united states, germany and belgium.

flex has earned its warm welcome to the neighborhood by proving itself one of the most noteworthy and successful additions this past year. and you need not flex your imagination to see why. -- flex mussels 174 e. 82nd st. between third and lexington avenues 212-717-7772 entrees: $16 to $27