Joseph Spector spent his first night at one of the city's hottest new restaurants looking as if this was where he belonged.

Tucked into his portable car seat and set atop one of the rear tables at Matyson, he was swaddled neatly beneath his cozy blankie. And despite a steady procession of adorers who continuously peeled back the covers to spy his fuzzy tufts of dark hair, Joseph coolly enjoyed an Olympic nap.

OK, so he's a newborn. But I doubt that even Rip Van Winkle could sleep through the jackhammer roar of this little restaurant. Bustling with a jovial mix of silk-scarved elders from the nearby Rittenhouse high-rises, stylish BYO scene-sters celebrating a birthday on the long banquette across the room, and wine salesmen test-sipping through several bottles of inventory, my sound meter leaped into a rare mid-90s decibel din.

There's nothing quite as romantic as trying to shout sweet nothings over your anchovy gnocchi and lobster-beet salad. But it hasn't deterred the crowds, so little Joseph had better get used to it. His parents happen to own the place, and Matt and Sonjia Spector have created a hot spot that resonates with the potential for some real staying power, bringing the bistro energy of the city's BYOB boom at last to the budding restaurant zone just north of Rittenhouse Square. (This one, apparently, is a BYO baby.)

It's a story that has happily repeated itself many times, infusing fresh dining life into every corner of the city, from Django in Society Hill to Pif in the Italian Market to Chloe in Old City. A talented young married couple do time in big-name restaurants, then, when the right moment arrives, strike out on their own in a modest neighborhood space.

For the Spectors, who met when they opened Bruce Cooper's Novelty in 2000 (he was the chef, she was the pastry queen and seduced him with brownies), the moment came last fall, when Spector's uncle offered them a lease on his old 19th Street butcher shop, Penn Center Prime Meats.

At 56 seats, it's slightly larger than your average Center City BYO, but the concept is the same. The decor is low-budget but cleanly styled and elegant in a Pottery Barn kind of way, with fabric throw pillows in a window banquette, tilted ceiling mirrors, and bouquets of flowers splashing color across the earth-toned room. Soundproofing, obviously, is a luxury the couple have yet to invest in.

The servers - youthful and engaging, but often running around breathless and out of sync - are another weak link early on. But that may improve when Sonjia, who timed Joseph's birth to within two months of the restaurant's opening, can spend more nights in the dining room.

She has thankfully managed to steal enough time to produce one of the city's most satisfying dessert lists. And her husband, likewise, has been cooking a reasonably priced New American menu that, despite a few glitches, has provided more than enough excitement to merit all the local buzz it has received.

Matt, who also did stints at Jake's, Brasserie Perrier, Susanna Foo and Trust, first caught my attention here at lunch. His fish sandwich brought a thick, succulent piece of grilled arctic char that was slipped into soft, warm black bread with horseradish cream and shaved cucumbers. A Black Angus burger served on a brioche bun beneath crumbly cheddar cheese and sweet strips of roasted tomato was one of the best I'd eaten in months.

The dinner menu was no less impressive. Tender potato gnocchi made perfect cushions for a zesty "puttanesca" garnish of olives, fried capers, and silvery fillets of fresh anchovy, whose piquancy echoed deep into the pillowy dumplings. Crisp triangles of garlic-infused polenta came topped with earthy mushrooms glazed in Parmesan cream. A tall cylinder of diced tuna tartare, layered with morsels of pineapple and tossed in a sweet and spicy jalapeno-vanilla-soy sauce, took on the flavor of some exotic red fruit.

Spector is a creative and sophisticated chef, capable of finding just the right odd flavor to give an uncommon spark to an old dish, such as the zap of jalapeño citrus butter swirling through his potato leek soup. An entree of sweet seared scallops paired with snappy beluga lentils and toasted walnuts was another subtle but striking success.

There were a few occasions when Spector overreached. The delicacy of his lobster and beet salad was overwhelmed by the sweetness of a vanilla aioli. The unnecessary addition of salt cod to a garnish of mashed chickpeas gave an otherwise tasty fillet of striped bass a jarring twinge of brackish funk.

More often, though, these dishes delivered the kind of thoughtful, full-flavored vision that seems like a steal at $21 or less. A sublimely savory New York strip basked in a sunset-colored sauce of chipotle pepper and blood orange that warmed the meat with a whisper of smoky spice and sour citrus. Rosy rare medallions of lamb loin, perfectly crusted with herbs, fanned over chewy pearls of Sardinian couscous and morsels of herb-infused tomato chutney. A juicy pork chop posed over squiggly noodles of spaetzle tossed with bacon, Brussels sprouts, and whole-grain mustard cream.

A special of crisply seared skate was so good beneath its glaze of brown butter and fried capers that it was easy to forgive the mound of underdone risotto it rested on.

Of course, Matyson also has a ringer in Sonjia's desserts, which may, in fact, be the best part of the meal.

I still dream of her apple strudel, an orchard of cinnamon-scented fruit wrapped in a band of sour cream pastry. Her homey apple turnovers, though, are just as good, residing inside a crust that shines with melted sugar. Then there were ricotta fritters, a handful of hot pastry puffs to be dipped in sour blood orange sauce. A delicate round tart was filled with lemon curd crowned with a whip of lemony meringue souffle. Homemade ice creams tasted of real mint and creamy peanut butter. A classic round of creme caramel melted on the tongue like vanilla silk.

And then, of course, there was her warm brownie parfait, revived as an occasional item from her days at Novelty. When you taste the sumptuously bitter, hot brownie pressing against the cold base of rum and cocoa semifreddo, it isn't hard to imagine how this all began, with a few scraps of brownie for the chef here, a few scraps there. Next thing you know, little Joseph has got a special new place of his own to call home.