I thought Roslindale Square was pretty well set for restaurants, with Delfino, Gusto, and Village Sushi. But Birch Street Bistro has eclipsed them all. Seldom has a restaurant outside the competitive zones shown such accomplishment at opening. Hardly anything on the menu is really new, yet everything has a twist or an improvement.

For the duck-confit spring rolls ($8), themselves a Frenchified twist on fusion spring rolls, the crucial touch is a hot, Malaysian-style pepper sauce that brings together the savory duck and more-traditional fillings, with a side salad of soba noodles and a few vegetables. On the three-tomato salad ($8), the red and yellow tomatoes were better than they had a right to be, even in late July, but the addition of morsels of fresh mozzarella made an extra dimension of contrast. For a cylinder of tuna tartare ($9), the bits of fish are held in enough lemon juices to ceviche-ify the outsides, while most of the flavor is sushi-quality tuna, with an underlying wisp of citric sauce decorated with black sesame seeds. Even a simple salad of Asian greens ($6) has a well-balanced raspberry vinaigrette to set off the spoon-shaped baby greens of tatsoi and other Asian cabbages and lettuces.

On the main dishes, I was immediately taken with the potato-crusted codfish ($18), because it’s the first time I’ve had the faddish platter when the crust actually was crisp. The garnish of micro beet greens is both a salad and a sauce for the sweet, mild fish. "Pink-peppercorn-crusted Ahi tuna, vegetable hash, celery root purée, pea broth" ($19) wasn’t all of that, but the tuna was large, neatly seared, and sushi-fresh. I’ve always loved celery roots in any form, with the mashed form being perhaps the most luxurious, and perfectly garnished with the pea purée.

"Artichoke and Fontina ravioli with sautéed prawns, fresh corn ragout, tomato fennel broth" ($16) again isn’t that complicated, because the corn and tomato components are merged into a thick, quasi-Italian sauce. But the chef adds chunks of sautéed baby artichoke and fennel to the mix, along with six head-on shrimp. The ravioli are nicely made pasta, and the artichoke-cheese filling is more subtle than most fillings. A wild-mushroom strudel ($14) falls short only because the mushroom mix is dominated by store mushrooms and doesn’t have enough woodsy aroma. (Memo to chefs: Costco has the best price for dried porcini.) But the strudel idea is entirely sound, and a nice nod to the phyllo-dough traditions of the older Greek- and Arab-American merchants of Roslindale Square. This vegetarian entrée also has very nice sides of quinoa, hunks of red and golden beet, and asparagus.

The wine list has an excellent innovation, which I’ve previously seen only at Troquet: many wines are available by the half-glass as well as the usual four-ounce glass. The 2001 Terra Rosa Cabernet Sauvignon ($4.50 half-glass/$8.50 glass/$29 bottle) is finished in California from Chilean wines, and seems to combine some of the best of both areas in a glass of straightforward fruit aromas with some solid structure to the flavor. The currently featured Morgan Chardonnay ($9.50/$40) is all California, and very oaky, not so buttery as stereotyped (and perhaps overly oak-aged) vanilla chardonnays of California. It was good with all our seafood entrées, and probably even better with oysters, which seem to love oaky chardonnays.

Desserts are again excellent, though the kitchen should probably not try to caramelize the mango slices on top of the lemongrass-mango crème brûlée ($7), as neither the fruit nor the rest of the crust was sufficiently crisp our night. The lemony flavor was excellent, but for contrast one should have riper mango, or a more deliberately mild fruit, such as papaya. But I love Key-lime cheesecake ($7), which blends the extremes of Key-lime pie with the approximate flavor of sour cream, in the traditional graham-cracker crust, in a postmodern cylindrical shape.

Banana-pecan strudel ($7) solves all the problems of last year’s banana-spring-roll trend, because the filling comes through the lighter strudel wrap so nicely. I would put chocolate sauce on this, but then, I would put chocolate sauce on a New England boiled dinner if no one were looking. The only weak dessert we tried was a trio of sorbets ($7) served in a martini glass. This came to the table soupy on a hot night, and most of the soup seemed to be from a weakly flavored white sorbet. Spoonfuls of orange passion fruit and red raspberry were very good.

Service was generally good, as our waitress knew the food and the wine list quite well. There was a long pause waiting for dessert menus, with, by that point in the meal, a full restaurant and a full outdoor patio. We had considered dining on the patio, even though it’s harder to taste outdoors, but gave up because of an aroma of soap from a nearby commercial laundry. These are the perils of outdoor eating spaces, although the more usual peril is cigarette smoke from smokers driven outside by municipal ordinance.

Inside, Birch Street is a surprisingly large room in all dimensions. Space like this just isn’t available for a moderately priced restaurant in the usual zones. The Bistro is only moderately loud, despite lots of windows, a bare-brick wall, wood floors, a duplex-height ceiling with open joists, and Norah Jones–y background music. Colors are muted browns and golds, with big mock-Spanish lamps and ceiling fans. The lower sound and color are relaxing, which makes the food taste better.

Robert Nadeau can be reached at RobtNadeau@aol.com