It's what Cichonski does with macaroni and cheese at his day job - as chef de cuisine of Lacroix at the Rittenhouse - that might be a little startling to comfort-food purists. And I'm not even talking about the decadent orzo macaroni with house-smoked salmon, rosemary-steeped brie cream, and brown butter panko bread crumbs that has been one of Lacroix's biggest lunch hits.

How about the molecular gastro-mac that Cichonski's crew pulled off for a recent wine dinner? Using silicone tube molds and a quick-set jelling agent called Kappa, they transformed a rich sauce of triple-cream Brillat-Savarin into springy noodle-shaped tubes - in essence, the cheese became the macaroni - served alongside scallop sashimi with caper-miso broth.

OK. Not everyone may be ready to cozy up to this sci-fi rendition of classic American comfort. But Cichonski is working the cutting edge of a much wider trend that has cooks all across the region embracing new possibilities for macaroni and cheese.

The phenomenon has been simmering for a decade, ever since the French Laundry's Thomas Keller published his iconic recipe for haute "macaroni and cheese," rarefied with butter-poached lobster, mascarpone orzo, Parmesan crisps and coral oil. But the movement to reinvent this inexpensive, homey indulgence has only intensified as the country has entered its economic downturn, and kitchens watch food costs more closely than ever.

Few dishes are able to both trigger warm childhood memories in diners and offer chefs such a blank canvas for culinary creativity. Kitchens are now adding everything from seafood to chile-spiced noodles to unconventional binders made from squash. The pasta shapes themselves have been a subject of variation, ranging from simple elbows to triangle-shaped tubes and tiny beads of Israeli couscous.

And every French bistro in town, it seems, is now suddenly broiling sides of macaroni "gratin." One Northern Liberties restaurant, Swallow, recently converted itself into an entirely "mac and cheese bistro," with mix-and-match blend-ins ranging from gyro meat to gorgonzola. Cajun Kate's in the Boothwyn Farmers Market even gives its tall wedges of crab- and tasso-ham-spiced macaroni the ultimate Louisiana flourish: a crisp in the deep-fryer.

"Macaroni dude!" bellowed a pair of wide-bellied bikers standing in line behind me at Kate's, calling in their regular order with two thumbs up.

Philadelphia's soul-food restaurants, of course, have long kept the steam tables warm beneath pans of Southern-style mac 'n' cheese, recipes rich with eggs and cheese that usually skip the roux. Delilah's macaroni is certainly the most famous, given national notoriety by Oprah, but the baked macaroni at lesser-known Deborah's Kitchen at 26th and Girard is my soul-food favorite.

Far more creative energy, though, is currently being spent upgrading the traditional béchamel-bound versions of the casserole with better ingredients and refined technique. It's a task being undertaken most heartily by the city's new French bistros, from Parc to Bistrot La Minette. It's only fitting, since Philadelphians were among the first in the young nation to taste mac 'n' cheese, when, in 1802, a French chef named Louis Fresnaye distributed a recipe for "vermicelli baked like pudding" to the colonials.

"It's food for babies in France," said Eric Ripert, the New York-based French chef behind 10 Arts at the Ritz-Carlton, whose creamy, ham-studded macaroni is my absolute favorite of the new lot.

The recipe was actually refined by 10 Arts' chef de cuisine Jennifer Carroll, 34, a Northeast native who was inspired by the macaroni her mother, Joan, still bakes annually for her birthday.

It is a series of tiny professional-chef touches, though, that elevate Jennifer's rendition to near perfection. The dustlike consistency of her sourdough bread crumbs lends the Gruyère crust a most delicate and golden micro-crisp. A judicious last-minute thinning of the béchamel gives the sauce an almost milky flow. Pushing the ham through a grinder, instead of merely mincing, helps the meat fluff the casserole instead of weigh it down.

As with many seemingly simple dishes, attention to details and balance makes the difference. Choosing the cheese is only the most obvious variable - creamy Jack or sharp cheddars and Gruyère? Chefs have also conjured distinctive recipes by swapping other key elements, often with the upgrade of hard-to-find ingredients.

At Talula's Table in Kennett Square, for example, Bryan Sikora and Aimee Olexy coax maximum flavor from the béchamel, infusing it with herbs, garlic and Dijon mustard. But it is the addictively earthy spice of a rare imported penne made from Italian peperoncino chile peppers that makes this casserole worth the drive. That key ingredient, made by Dalla Costa, is impossible to find locally beyond Talula's market shelves, so you'll have to visit, even if you want to make it yourself. (In a pinch, a dash of fresh chili powder can stand in.)

At Sovana Bistro, also in Kennett Square, it is the diminutive shape of the pasta that allows chef Nick Farrell to transform the homey flavors of the dish into a decidedly elegant garnish. The beadlike pearls of Israeli couscous, enriched with a flourless fondue of fontina, Gruyère and Parmesan, emphasize the textures of seasonal ingredients - local mushrooms and diced butternut squash - beneath a crisply roasted breast of chicken.

Seasonality is highlighted even more vividly at Cooper's Brick Oven Wine Bar in Manayunk, where pureed butternut squash, sturdy pasta, ricotta, and mozzarella cheese are the essential ingredients. By replacing the roux-based béchamel entirely with pureed squash as a binder, chef Bruce Cooper also maximizes his ability to assemble the casserole at the last minute from components prepped well ahead of time (low-gluten squash, he said, unlike béchamel, won't thicken further in the fridge.)

For summer, Cooper is already planning to replace the squash with corn. Or perhaps a mac 'n' cheese with stewed tomatoes.

"It's simple, people just get it and share," said chef Cooper. "And we sell a good amount of it."

It's a far cry from the boxed macaronis and powdered cheese sauces of our past, but not quite the experimental "gastro mac" of our future, either.