An old pharmacy's new prescription is affordable fare inspired by French bistros.

Curios play up the restaurant's apothecary past. Photography by Vicki Valerio

The story of Rx has been repeated countless times these last two years: Restaurant-deprived neighborhood attracts young talent to open ambitious, affordable BYOB.

In this case, the setting is deep in West Philadelphia, a residential area with grand houses that in recent years had made a big comeback.

If the customers waiting around the coatracks for a table at Rx are any indication, the gentrification (or Penn-trification, to be more precise) is well under way. Weeknights bring the mostly neighborhood crowd that owner Greg Salisbury expected when he rehabbed Rx (pronounced Rex) from an old corner pharmacy: Penn students, tweedy academics, and a contingent of low-key locals who never gave up on the area.

Weekends, though, have seen an influx of designer sweaters, meticulous makeup and pricey boutique wines, sure signs that news of Rx has stirred a buzz among the dinerati, who, before the recent bistro boom, would more likely have strolled Walnut Street or chic Old City than ventured into an area known mostly for bargain Ethiopian and Indian eats.

It's no small irony, since Rx chef Ross Essner made his name at Bleu, Neil Stein's tony cafe on Rittenhouse Square. The menu at Rx, which Salisbury calls "feel-good food," isn't all that different, mostly simple French-bistro-inspired comfort fare made with fresh local ingredients and priced at $17 or less.

And when the kitchen is on its game, it captures just the right balance of style and unpretentious good cooking.

The grilled hanger steak is the centerpiece of one of the best steak frites in town. The charred slices of tender beef are stacked like dominoes over creamed spinach and crisp (though not homemade) frites.

The seared salmon is somewhat plain, but its costars are intriguing: a mound of tasty lentils ringed with silky white cauliflower puree and a sweet-tart reduction of port and blood oranges.

Beneath a tricornered cap of puff pastry, escargots nestle with mushrooms and cubes of celery root in a buttery sauce studded with cloves of roasted garlic.

At lunch, the turkey meatloaf was irresistible — tangy and moist with shredded apple.

If Essner's cooking is the invitation to come, Rx's bright little dining room offers a reason to stay. Previously a catering facility and before that a takeout shop, the space has been tastefully spruced up with banquettes set beside wide windows; gold-accented white moldings; and sheets of metallic fabric that billow beneath the ceiling lights.

A wall-length wooden case is crowned with etched glass panes that read "Rx," a handsome reminder of the room's origin as an apothecary. It's a motif played to the hilt, with nostalgic knickknacks scattered around the room, from the antique doctor's scale (in a restaurant? Yikes!) set between two tables to the glass beakers on the shelves.

The glass petri dishes filled with olive oil were a bit much, though. I wasn't about to be caught dipping my bread in what looked like a medical specimen.

That's not Rx's only flaw. The room gets so noisy that it's hard to carry on a conversation. And the wait for one of the restaurant's 32 seats can be unnerving, especially as Salisbury fretfully shuffles his tables for two like a Rubik's Cube to put together seating for four.

During my meals, the servers were well-meaning but off-kilter, forgetting to bring water, neglecting to offer a bread basket until we were halfway through our entrees, and knocking over great piles of dishes at regular intervals all evening. The grand finale was a crash inside the dessert case, which dashed hopes of sampling the carrot cake.

Essner's kitchen occasionally slipped up, too. One evening the Thai curried mussels were gloriously addictive, basking in a gently sweetened spicy coconut broth; another night they were sloppily piled with empty and broken shells, not to mention a stray rubber band.

An appetizer of Severino brand gnocchi was disappointing, too gummy to compete with the many ethereal homemade versions around town. And my black cod, a trendy Asian-accented favorite inspired by New York's Nobu via Stephen Starr's restaurants, was far too sweet, lacquered with a treacly miso glaze and garnished with gingery mashed yams.

Still, more often than not the food was appealing. The meaty duck spring rolls and an appetizer of tempura-fried scallops with spicy mayonnaise got the Asian flavors just right. Some beautiful seared scallops were equally smart, evoking a Caribbean mood with their fragrant coriander crust and accompanying mango and avocado salad.

A pan-seared whole Pocono trout, stuffed with mashed potatoes and ringed with horseradish cream, looked a little blobbish on the plate. But the fresh taste of the delicate fish paired so well with the other flavors that it was hard to resist.

Nicely browned skate, the fish darling of the current bistro boom, was prepared with textbook care. The crisp ribbed fillets were stacked like cards atop a refreshing salad of shaved fennel and blood oranges.

The dessert case was a study of bake-sale homeyness, though some offerings were more inspired than others. I've never encountered a harder brownie than the one that arrived at our table, split and sandwiched around a scoop of ice cream. The individual chocolate bundt cake also was dry.

But the pineapple upside-down cake was lusciously moist with sticky fruit. The chocolate pot de creme could have packed more power with extra-bitter chocolate, but it was undeniably creamy and indulgent.

The warm peach cobbler had a soft, crumbly pie-spiced topping. And the Jewish apple cake was a study in the architecture of comfort — a humongous wedge of butter-crisped crust that yielded to a tender heart of sponge cake perfumed with fruit.

If ever there was a "feel good" finale to a story you've heard before, this was it: one slice of cake — and a slice of West Philly — that I'd gladly visit again.