Ask me what I want to eat at this very moment, and my answer would definitely be the sea bass at Cosmos. The succulent fish is prepared confit-style and served over what appears to be risotto but turns out to be shaved cauliflower, slow-simmered in vegetable stock until it mimics risotto. Then the server adds a finishing touch, pouring out a pristine tomato broth with a practiced flourish.

The dish is a Cosmos staple, although by the time you read this, chef Stephen Trojahn and chef de cuisine Håkan Lundberg will have replaced the sea bass with a more seasonal halibut. Why change a good thing? That would seem to be the lietmotif of Trojahn's tenure. Trojahn has been running the food operations at the Graves 601 hotel for about 18 months, and has continued on Cosmos' trajectory of unadulterated and unapologetic luxury.

It's also a lot of fun, particularly at dinner, where Lundberg flexes his molecular-gastronomy muscles. Chicago is the epicenter of the country's M.G. craze, but aspects of this fascinating kitchen-as-chemistry-lab trend have trickled north. Lundberg is probably the region's most overt local convert, but his is a reserved form of mad-scientist cooking.

Lundberg's most entertaining showstopper isn't on the menu. He dubs it an "explosion," and it appears as a between-course interlude. The name fits for what appears to be a frozen gelatin-like sphere served in a shot glass. As the thin membrane quickly thaws in your mouth, it reveals a quick flashbulb-fast burst of lemon or raspberry. Suddenly a palate-cleansing sorbet feels very Mamie Eisenhower.

"That's what molecular gastronomy is all about," Trojahn explained. "Not masking any true flavors, but getting people to think about the way your mouth feels different flavors. We just don't get too crazy with it, to the point where people can't recognize what they're eating."

Yes, the flavors come through loud and clear, and the visual freakout factor is almost nonexistent. I loved a rectangular terrine of slow-poached shrimp, which preserved the crustacean's lively texture while cleverly upping the flavor ante. The glories of Minnesota-raised duck were amplified by a similar low-and-slow cooking technique. Lundberg and Trojahn play with wild rice by popping it like popcorn, crushing it and using it as a crust for a stunningly seared ahi tuna. A gorgeous avocado ice cream adds a chilly luster to sushi-grade raw tuna.

One night I stopped in for the evening's tasting menu, and I was not disappointed. A herb-flecked lobster salad was cool and clean. A brûlée torch gave a surprising crunch and sparkle to a luxe foie gras terrine. Then came slices of pork loin over seared polenta and dressed with a barbecue-style sauce kissed with truffles.

Classic dishes are just that, particularly at breakfast and lunch: a swell nuevo lobster club, Benedicts built with seared foie gras or divinely lumpy crab cakes, a high-class grilled cheese, the best pad Thai in town.

Extra touches abound. Dinner guests are greeted with a delicious salutation from the kitchen -- perhaps a bit of poached lobster. When the check arrives, its final tally is softened somewhat by an array of exquisite chocolate truffles. And Trojahn sources premium local ingredients while simultaneously demonstrating the virtues of first-rate imports.

The sleek and sophisticated setting remains every inch the luxury property it purports to be. But Cosmos has one major flaw: its cloistered location, tucked away on the fourth floor of downtown's schlockiest piece of real estate, Block E. I make my living obsessing about restaurants and yet Cosmos is constantly slipping my mind.

My foolish mistake. Don't make it yours.