Grand Old Patty: Ian goes on a beefy binge at Burger Bar and Sub Zero New American Burger Restaurant

Likewise, the "Black Jack" burger, chosen from among the six "Chef's Burgers," was good but didn't seem deserving of special attention: Black Angus beef, tangy Monterey Jack cheese, tomato, lettuce and a spread of tapenade on toasted ciabatta. Sides were passable, but not up to the level of the burgers. The fries were crisp but lacked a distinctive flavor; sweet-potato fries provided flavor but weren't especially crisp. I liked the onion rings — though, again, they didn't strike me as anything better than what I'd find at a more modest burger joint.

Sub Zero New American Burgers isn't nearly as high-profile as Burger Bar. It opened in November, an extension of the popular Sub Zero sushi and vodka bar. The new room is smaller and much less sleek than the original Sub Zero; it's a dimly lighted space that offers freestanding tables and banquette seating. You can order sushi in the burger restaurant, but you can't order a burger in the sushi restaurant.

As at Burger Bar, the menu — developed with Eric Brenner of nearby Moxy — is split between burgers designed by the kitchen and burgers you build yourself. Sub Zero's selection of toppings isn't as broad as Burger Bar's, but unless you must have marinated anchovies, you might not mind.

On my first visit, I ordered the American Kobe beef, medium-rare, with cheddar and bacon. My wife ordered Black Angus beef, medium, with Gorgonzola and caramelized onions. We received a Kobe beef with cheddar and onions and Black Angus with bacon and Gorgonzola. Both burgers seemed closer to medium than medium-rare, and my Kobe beef wasn't as luscious as it had been at Burger Bar. The Black Angus burger was good, though, its straightforward beefy flavor nicely contrasted by the pungent blue cheese.

On a subsequent visit, I tried two of the burgers designed by the kitchen. The lamb burger was pleasant, if a little bland. The meat was tender, but the strongest flavor came from a smear of feta cheese; a dollop of hummus offered more texture than taste. Mint, promised on the menu, was nowhere in sight. The "Slinger" burger matches Black Angus beef with, yes, a fried egg, cheese and chili. I admired the audaciousness of this burger, and it might have worked had the chili been more distinctive. Instead, the boring flavor of chili mix grew tiresome.

Here too the sides were underwhelming. The French fries were especially lackluster, and the barbecue sauce the restaurant offers for dipping was syrup-sweet.

Once you strip away all the add-ons, both Burger Bar and Sub Zero serve good burgers, and, occasionally, very good burgers. But for establishments that have made burgers their sole focus, you have to wonder whether they're offering anything truly different from O'Connell's, Seamus McDaniel's, Blueberry Hill or whichever your favorite burger joint may be.

I never thought I'd ask this about a place where you can get foie gras, black truffle and American Kobe beef in the same dish, but...

Is that all there is?