Upgraded from 3 bells.

Recipe for a great Philadelphia BYOB: one hardworking chef in the kitchen, one charming wife running the 30-seat dining room, and legions of devoted regulars who toast their favorite gem with glasses of their own grand cru wine.

We've seen this ingredient list before. But rarely has it achieved the magical, marrow-shined luster that is Bibou. The chef, of course, is Pierre Calmels, the brilliantly talented expat from Le Bec-Fin (and Daniel), who left haute cuisine to plunge deep into the rustic soul of his native French bistro tradition, pig parts, game birds and all. His wife, Charlotte, meanwhile, takes the role of astute hostess to the next level, reciting guests' long tasting-menu histories at the same moment she reserves their next meals on a laptop beside their table.

And reserve they do, with more than half the room set aside every Wednesday and Thursday for standing commitments, most of them wine lovers who find Calmels' flawless French cooking the city's best match for their trophy Burgundies and Bordeaux.

Calling Bibou merely a "bistro," though, can be misleading. Yes, the decor is simple, with gray wainscoting, white lace on the storefront windows, and an open view into the rear kitchen where you can see Calmels and his longtime sous, Ron Fougeray, roasting long marrowbones stuffed with chanterelles and Scottish partridge in Madeira sauce. But there's an extraordinary personal contact here between the Calmelses and their patrons that is rare and rewarding.

Bibou always has excellent dishes for less adventurous eaters (hanger steak, trout, crab salad) on its small a la carte menu, as well as signatures such as the foie gras-stuffed pig's foot. But this kitchen's talents are most evident in the ever-changing seven-course $70 tasting.

Calmels is the rare chef with the polish and feeling to make the oldies seem fresh and new. That could mean transforming a peasant staple - pig ears - into ethereal translucent noodles tucked inside a flaky phyllo rectangle. Or channeling Escoffier elegance with black bass rolled around tarragon fish mousse over a retro sauce Joinville blushing with lobster butter and black truffles.

His turban-shaped Pithiviers filled with oregano-scented lamb and foie gras lent true pastry luxury to a perfect lamb chop. Silvery daurade dabbed with rosemary froth, meanwhile, evoked the Mediterranean.

I still dream of the floating island he turned into a pyramid of meringue studded with almond nougatine, bobbing over goat's milk crème anglaise for dessert.

I'll be intrigued to see what's next if Pierre and Charlotte finally receive their green cards this spring. The possibilities are grand: A larger second place with a liquor license, perhaps? Pierre knows this BYOB is sacred.

"We'll always keep Bibou as our baby and my little garden of ideas," he promises. "But we'll at least be able to finally unpack our suitcase."