On a recent Friday night, I found myself waiting hungrily for dinner right where a wall used to stand between the storefronts at 4365 and 4367 Main Street in Manayunk.

There's a hole cut through now, forming a common foyer between two restaurants, the upscale mainstay, Jake's, and its casual new sibling, Cooper's Brick Oven Wine Bar, where a clothing store used to be. To stand directly between them is to observe more than merely a sharp contrast in styles, but a side-by-side snapshot of two distinct eras in Philadelphia dining.

To my right is the high-style classic Jake's, its vaulted-ceiling room a tranquil yellow oasis for silver-haired diners supping on the enduring New American standbys - duck confit spring rolls, grilled calves' liver, cider-soy barbecued salmon, and $39 steaks - that have made it the fine-dining champ of Manayunk for 21 years. It's a stylish survivor in a neighborhood that's seen its cachet rise and fall over the last decade. But like so many white-tablecloth eateries across the city these days, Jake's dining room has been less than full recently, despite slightly lowering its menu prices and allowing BYOB on weeknights.

On my left, meanwhile, is the happy pandemonium of Cooper's, where a swell of spirited young drinkers jostles up to the long bar with glasses of grüner veltliner and Belgian ale, nibbling house-baked bread balls and brown bags of fresh potato chips dusted in vinegar powder as they wait - an hour or more - for a seat.

And they will wait, because Cooper's has clearly tapped the casual zeitgeist of 2008, from its small plates and gourmet pizzas at $15 and under to the fact that its 30-label wine bar is also bolstered with 20 serious craft beers. The laid-back vibe of the room, with deep pleather booths, tall tables, and an earth-toned abstract wall mural, is a departure from the tony chic that has been Jake's signature for so long.

But with a shared kitchen and service staff (and a partially shared menu), I've come to think of these two spots as the split personality of one restaurateur - owner and executive chef Bruce Cooper - rather than as distinct operations. (In fact, you can order off both menus from each dining room.) And the addition has injected some serious energy and fresh traffic - essentially doubling Jake's size, but quadrupling the number of meals Jake's once served.

What distinguishes this wine bar from so many other new small-plate bars around town is that Cooper, 54, has taken the same serious approach to his bistro menu that made Jake's a fine-dining standout to begin with. His awesome new "Jake burger," a 10-ounce pillow of meltingly rich prime beef topped with an oozy flow of caramelized onions, mushrooms and Lancaster cheddar, is already becoming a popular item on both menus. (Some regulars in the Jake's dining room, loath to completely shed their high-end habits, have taken to ordering it alongside chestnut-stuffed quail and BYO bottles of luxury wine.)

It is in the back of his new place, though, where Cooper can be seen most nights, happily tending the flickering hearth of his new toy: the $40,000 wood-fired pizza oven that has ignited a tasty new repertoire from him and Jake's chef, Abdoulaye Soumah.

There are the pizzas, of course, which are excellent, their heat-blistered crusts (more crackery flatbread than stretchy pizza dough) laden with well-parsed toppings. The margherita was a fine version of the minimalist classic, its basil-tinged tomato brightness spotted with milky clouds of Claudio's mozzarella. The "spicy meatball" dialed the zestiness up a notch, with a twinge of chile-flake heat beneath tender veal meatballs and creamy Mancuso ricotta.

The "fire-roasted onion" was a bit too heavily dressed, but it was the exception. Another pie remained crisp even beneath the weighty luxury of thickly sliced king oyster mushrooms and truffled cheese. Cooper's most distinctive pizza, scattered with tender shreds of short rib, horseradish crème fraiche, and a reduced port drizzle, managed to distill a country-club banquet down to an elegant micro-crust.

Actually nabbing a no-reservation table to sit and dig into the menu can be one of the frustrating downsides here, especially on weekends when the overburdened staff took several minutes simply to clean the vacant tables. They were efficient and pleasant enough once we were seated, though for real advice on the numerous wines by the glass, consult with manager Evan Oxenfeldt.

In all, it's not a premium selection, but rather, a good list of well-chosen value wines that ranges internationally from St. Urbans-Hof riesling to Four Vines zin without the predictable cliches (only one cabernet and one chardonnay!). The prices, mostly around $11 or less, are fair for generous six-ounce pours. For pure quality, though, one can do even better with one of the beers, a goblet of Atomium grand cru or Saison Dupont from Belgium, perhaps, or a Fat Dog Stout from Stoudt's.

Cooper's menu is really the best reason to visit, and for more than just pizza. There are some excellent cheese plates, including creamy Green Hill from Georgia with strawberry-thyme preserves, and the Gruyère-like Pleasant Ridge from Wisconsin with burnt onion jam. There is a bountiful charcuterie platter featuring Benton's aged country ham - Tennessee's stellar answer to prosciutto.

The entreelike braised short rib was one of my few disappointments, too much like boiled brisket in soupy broth with rubbery little polenta dumplings. But I enjoyed virtually every other dish - a distinctively seasonal mac & cheese bound with pureed butternut squash; oven-roasted tender shrimp topped with herby chimichurri; roasted beets scattered with the sweetness and crunch of almond-thyme praline. And I loved Cooper's temperature twist on the old Caprese, roasting a full vine of cherry tomatoes, then setting them hot atop a cool cloud of milky stracciatella curds.

There are also hearty entree salads, such as the chicken cobb with Benton's bacon and Roquefort dressing, that should please the Manayunk ladies who lunch - those faithful shoppers who have fueled Main Street through its ebbs and flows. I wonder how many of the old guard will continue to gobble down the oniony Yassa chicken, a staff meal-turned-menu star from Soumah's native Guinea, once it gets out that it's not made with boneless white meat. ("I was surprised we could sell chicken thighs!" muses Cooper.)

Ah, the freedom of bistro cooking!

At least pastry chef Debbie Tonsey's desserts have stayed a constant. The same well-wrought classics that have long anchored Jake's sweet menu for years are served at Cooper's, too: the crisp profiteroles with house-churned ice cream drizzled in shiny dark chocolate, the cinnamon-roasted apple cobbler with spiced molasses ice cream. And, of course, the famous cookie taco, an ice-cream sundae baubled with berries and white chocolate curls in a sugar-crisped tortilla cradle.

As the Jake's crowd learns to welcome its casual new sibling, it's a welcome taste of a festive, familiar comfort.