If you could sketch a restaurant on a blank page to capture the dining spirit of late 2011, it might very well look a lot like a.kitchen.

The ambience would be laid-back and linen-free. The cafe windows would be swung open to the Center City streets beneath crisp black awnings, while inside, blond wood banquettes front a marble chef's counter that rings the lively open kitchen. And its mission? A modern hybrid space: part hotel breakfast cafe, part wine bar, part kitchen atelier, where the polished young crowd can scale up at whim from nibbles to a full-blown meal and the small plates sparkle with just enough vivid flavors to generate a serious foodie buzz.

At less than $20 a dish, each one toes the delicate line that defines the catchphrase "casual sophistication." It's an elusive notion, a tricky balance between simplicity and substance, affordability and high-end tastes. But as this new cafe-restau-lounge settles into the facade of the Korman's "aka" extended-stay hotel north of Rittenhouse Square, a.kitchen has dialed in that frequency (after early fine-tuning) with a pitch-perfect ear.

How about a warm dome of hand-pulled mozzarella burrata stuffed with a creamy core beside fresh melon salad ribboned with salty country ham? A Jersey fluke crudo was dazzling, the diced fish mingling with hot cherry peppers and yellow plums, their sweet-heat contrast amped by an earthy paprika-oil glow. Just as satisfying was a simple pork blade steak, savory with rosemary and a maple-vinegar tang, posed over a succotash of summer's last gasp.

And, of course, what culinary hotspot doesn't have a signature low-food tweaked to artisan heights?

I thought I'd already tasted them - hot dogs, pierogies, tater tots - until I met the delicately griddled crunch of a.kitchen's scratch English muffin. The roasty cornmeal bottom gave way to butter-toasted crags inside its deflated-tire middle, then a moist, almost underbaked-biscuit core: a pedestal for breakfast bliss. Add a slice of PorcSalt's country ham, or sausage and an oozing fried egg, and you'll be holding a combo that redefines the local breakfast sandwich. Not to mention reboots a star chef's career.

Who knew English muffin-dom even had such powers?

It's not entirely a surprise given the man behind the menu. Bryan Sikora has long been one of our region's most gifted cooks, but he'd fallen into a nomadic funk since leaving Talula's Table, the Kennett Square sensation he opened with his now ex-wife after Django, bouncing between Delaware, Allentown, and R2L, for five minutes each.

I hope he has found a comfortable enough perch in this 60-seat dining room to hang around for a while. Because three satisfying meals have reminded me just how much I love his strikingly soulful food.

Scallops and kraut sound straightforward enough, but the choucroute delivers layers of flavor, from cooked-down onions and fennel to the porky oomph of rendered salami, sausage, and bacon. Add the pop of rehydrated mustard seeds, and though the starter is tiny - just three little coins of browned scallop - each one resonates like a chorus.

The crab and farro is a study in subtle textures, the downy jewels of sweet crustacean mounded with the bitter crunch of shaved radicchio over the earthy grain's chew. But there's also so much flavor in the tarragon yogurt dressing that holds it all altogether, I wonder why crabcakes would ever bother with binding and heat again.

Sikora takes on the current meatball mania with his own sharp rendition, cuminy spheres of house chorizo braised with tomatoey seafood broth, then topped with green olives and curls of calamari cut like trompe l'oeil noodles. Amazingly tender octopus arms, meanwhile, scroll between juicy cubes of charred watermelon and musky dabs of a harissa emulsion.

This is exactly the kind of food the Korman's consultant, David Fields, could have hoped for when he conceived the a.kitchen concept: "sophisticated but not fancy; thought out but not overly precious." It's a welcome reversal from his approach to Salt, the avant-garde dining boutique he launched near Rittenhouse that favored "intellectual" over "approachable." It was relatively short-lived.

Fields' savvy for all things alcohol is one of a.kitchen's greatest assets. He has assembled one of the city's more interesting cellars (already 200 labels strong), built on small producers from such in-the-know Euro regions as the Loire and Alsace, with enough choices in price and format to give the Square's anemic wine-bar scene (aside from Tria) a welcome jolt. The choice of Counter Culture coffee (edging its way into La Colombe's restaurant monopoly) gives yet another reason to visit for breakfast, where I also devoured a frittata snappy with corn, hot peppers, and more of that irresistible chorizo.

I wish Fields and designer Edward Asfour had done more to dampen the hard surfaces that make this room so noisy. But all the pale wood, mirrors, and soft Italian lighting do their part in placing the spotlight where it belongs - on this kitchen's vibrant cuisine.

There's been a transition here since the opening, says Sikora, as the menu sought the ideal balance of simplicity and substance, gradually elaborating the plates while retaining their clean compositions. By September, there was hardly a dish that lost my interest.

The sole exception, ironically, was the biggest dish - a $39 New York strip of dry-aged Select Angus. It was the only plate over $19 - and seemed cumbersome and boring. I found more satisfaction in small ideas executed to perfection: bucatini tossed in a creamy flow of sheep's milk cheese flecked with black pepper in cacio e pepe; some pristine asparagus and baby artichokes griddled to a snap over pecorino cream beneath a pan-fried egg and the crunch of toasted bread crumbs; delicate beech and maitake mushrooms blended with molten Taleggio inside tender crepe parcels over the vivid green of watercress puree.

Sikora's meat dishes hit the mark, too, from tenderly braised veal ragu tossed with frilly-edged tagliatelle to a grilled lamb, rubbed in black olives, with zesty chimichurri and the bitter bite of wilted treviso. The braised chicken-leg risotto was milky sweet with corn stock, then smoky with crunchy bacon dust.

But it's the fish dishes, always the most delicate, that show a kitchen's skill. A gorgeous grouper with fresh favas, fennel-scented fava puree, and red-pepper piperade reminded me of Django. Crisped skate Provencale was ringed by a piquant necklace of capers. A gratin of airy gnocchi, meanwhile, mixed into bechamel with smoked haddock and snappy summer squash, is the kind of dish I'll be craving as the fall chill settles in.

I can do without the over-gelled chocolate panna cotta, my one dessert disappointment. But there were warm plugs of fresh-baked shortbread with lemon curd, as well as chewy almond macaroons, to fill the void. And I was especially glad to once again see that goat cheesecake (with tart riesling sorbet), a longtime Sikora signature that has stuck with the chef through his trials and travels. As he cooks his way back into our consciousness in this deft showcase of Philadelphia's dining present and future, it's a sweet reminder that a little taste of the past isn't all bad, either.

Join Inquirer restaurant critic Craig LaBan for an online chat Tuesdays at 2 p.m. at http://go.philly.com/phillytalk.