'Jackets required" is one dining-room edict that's doing a quick fade to endangered status. And while I don't regard my blazer with quite the disdain I have for ties (and the stuffy chokehold they once clamped on upscale dining), it is not a restriction I'm going to miss terribly.

After all, the fact that serious cooking is simmering now in more casual venues is one of the great triumphs of America's evolving food scene. Add in a dodgy economy that's put a damper on the high end, and it's no wonder so many gastronomic icons have unbuttoned their double-breasted dress codes to remain relevant.

But if we need to retain one holdout for old-school decorum, it might as well be the Fountain Restaurant at the Four Seasons. The luxury landmark underwent a major transition this year when longtime executive chef Martin Hamann left for the Union League, ceding the top toque to an out-of-towner, Rafael Gonzalez.

Some might have fretted that this was the beginning of the end for Philly's palace of posh. But, thankfully, that's hardly been the case. In fact, my recent meals were so spectacular, I'd look forward to another dinner there even if the Fountain required straitjackets and gravity boots.

No doubt veteran Fountain waiters like Jim Miller and Vincent Russo could handle that awkward situation with their usual seamless, silver-spooned aplomb. And from whatever angle you regard these artfully crafted plates, there's no mistaking their stunning beauty.

A fan of amazingly tender grill-marked rabbit loin spreads beside a majestic pyramid of pasta filled with juicy braised leg meat and leeks. A tempura-fried squash blossom on top was so lightly crisped it practically hovered above the dish. A slider of ground venison and foie gras with melted cippolini onions and a sunny-side-up quail egg ratcheted the gourmet burger wars to new heights. And I'm still dreaming of the amuse-bouche morsel that opened my second visit, a creamy pillar of white grits studded with pancetta, sweet corn kernels, and shaved truffle. Inside the bubble of unbridled gastro-indulgence that persists within the Fountain's richly wood-paneled walls, even the pre-meal freebies are master productions.

Geez, even the city tap water here is noticeably more crisp than usual: "It's triple-filtered!" Russo beamed.

That the Fountain installed a filtration system to replace all the expensive bottled European water it used to cook with is a nod as much to economy as to green ecology. And though Gonzalez said business has "only" been off about 10 percent from last year, there have been a few light recession concessions – all of them good. The historically gouging wine list now has slightly lower markups, plus 60 wines under $60. There's a new $62 tasting menu on weekdays (versus the more expensive, larger weekend options). And even prices on the a la carte menu, whose entrees once hovered obscenely in the $50-plus range, have been lowered an average of $7 a plate.

How much of that is due to Gonzalez's arrival is unclear. It also remains to be seen how much artistic impact will eventually come from the well-pedigreed Gonzalez, 35, a veteran Four Seasons exec-chef (Vancouver, the Pierre) and alum of Jean-Georges, Boulet Bakery, and Le Bernardin. Already, the food seems slightly lighter, less drenched in thick demiglace than in the past.

No doubt dinner here is still a gold-plated indulgence. But compared with the astronomic fees people now eagerly pay for grilled slabs of beef, this is a fair price for a genuine expression of culinary art. And this kitchen's amazing consistency is, more than anything, a tribute to the longevity of its talented kitchen stalwarts - night chef David Jansen; chef tournant William DiStefano; day chef Ralph Costobile; banquet chef Joe Drago; and pastry chef Eddy Hales – who have more than a century of Fountain experience among them.

Unlike some kitchens, though, that august experience has never translated into stale cooking. Quite the contrary: The Fountain remains one of the most vital, worldly and witty kitchens in town. "Steak and eggs," for example, will never be the same for me after the Fountain's rendition, a rosette of beef carpaccio topped with crispy rails of Pont Neuf potatoes and a comet-shaped orb of tempura-fried egg yolk, whose exquisitely delicate micro-crust released a brilliant yellow gush at the tap of a fork. A special lamb rib-eye offered a polished riff on Middle Eastern street food, from the za'atar-dusted tender lamb to an almost fluffy falafel patty of herbaceously ground chickpeas, and a deconstructed tzatziki that stuffed spiced Greek yogurt inside a baby cucumber.

There are still plenty of classic indulgences, though they're framed with a breath of seasonality. A butter-soft veal tenderloin, pinned by herbs atop an earthy farro grain cake, is ringed with the springtime sirens of morels and fiddlehead ferns. There was a silvery ribbon of gristle in our prime sirloin steak: the only major flaw in my meals. But the dry-aged meat itself was sublime, and its presentation – topped with a bundle of baby carrots tied with ramps and a sheer flower made from crisped potato petals – was an edible still-life.

The lobster duo, with a buttery plume of tail and huge sauteed shrimp ringing a large ravioli filled with lobster, potato and leeks, is perhaps the city's most elegant lobster splurge.

There were delights on every plate: a surprisingly earthy lamb minestrone, poured tableside over a mound of ditalini pasta, tiny lamb meatballs, and mint pesto; roasted monkfish atop white beans studded with crawfish and anise-flavored pork belly; seared tuna with creamy oyster and fava bean chowder; plum-vinegar-slicked duck stacked atop a crispy pastry envelope stuffed with Asian black-bean puree.

There were pitch-perfect desserts from Hale, including the potent cocoa power of the city's purest chocolate souffle, a banana tarte tatin, exquisite petit-fours, and the hot-cold buzz of a deep-fried bar of cream cheese ice cream.

Sommelier Scott Turnbull uncorked some lesser-known jewels from the 400-label wine list for stellar pairings, including a spectacular Rhone-style white from California (L'Avion, $70) and a plucky red Spanish moristel that, at $38, may be the first genuine "bargain" wine I've ever tasted here.

It was, all around, another magnificent performance from one of Philly's most enduring havens of luxury. There was, however, one uncharacteristic service flaw: a shrimp cocktail that - gasp! - had not been delivered.

May you only be blessed with such a goof. Because no restaurant knows how to apologize with the decadent penance of the Fountain, which lavished our table with treasures from the cheese trolley, a neatly packed cooler of shrimp on ice for "take-out," and packages of fresh palmier pastries as we glided out the door.

The fuss of such formality may be fading quickly in the rest of our dining world. But thank goodness it's still alive and vital at the Fountain. Hand me my blazer.