There is the inevitable liquid nitro smoke fuming around the tables at Marigold Kitchen. There is foam, too, my favorite being a cloth-bound cheddar whipped to a pouf inside the miniature hollow of a fingerling potato skin. There are "ham bubbles" that pop over warm demitasses of silky cauliflower and white bean soups.

And there are a shocking number of chefs in the kitchen (sometimes 10!) working over nearly 800 little plates on a busy Saturday for the nightly tasting meals at this homey but wildly ambitious 46-seat BYOB in West Philadelphia. Some chefs swing mallets to smash frozen orbs of winter-spiced foam for the warm chocolate soup. Others use syringes to form multicolored, frozen "Dippin' Dots" that, in the mouth, melt to vividly evoke gazpacho, or an autumnal tune of gorgonzola, cider, and bacon.

Bubbles, foam, and smoke, of course, are the cliches of molecular gastronomy, the science-driven edge of contemporary cooking that, in my experience, too often distracts young chefs with shiny gadgets when they should just be thinking harder about harmonious plates.

Marigold's Robert Halpern wasn't exactly one of those when he arrived here in fall 2009 as owner-chef, taking over from Steven Cook and Michael Solomonov. Halpern's early days were marked by plenty of solid dishes on the à la carte menus. But the Villanova native was still a chem-cooking novice - an unschooled chef who worked distinctly different kitchens at the Moosewood and Coyote Cafes, plus an internship at Alinea, and who was still finding his voice with avant-garde tools.

He's not necessarily innovating here yet. But four years later, with Marigold recently abandoning a traditional menu for kitchen-directed $85 surprise tastings of 16 (or so) plates, it's clear that diners are in good hands. The 37-year-old and his young but enthusiastic staff have begun to come of age and find a voice. And a meal here finally feels like a destination experience greater than the sum of its culinary tricks.

I can still taste the warm rush of liquid corn bursting from a single ravioli at an early October meal, its sweetness tinted with cumin salt. By my winter return, the center was butternut squash, with banana-flavored salt adding an unexpected tropical note.

Such surprising tweaks were scattered throughout, like the dark chocolate tuilles that added bittersweet crunch to tiny foie gras cookie sandwiches. Or the pickled jalapeños that sparked against the creamy richness of truffled mac 'n' cheese with peekytoe crab. Or the baguette-flavored ice cream that added a bread element to deconstructed panzanella.

The intense labor that goes into transforming so many elements can have a reverse benefit. When an ingredient is left in its relatively natural state, like the Painted Hills filet mignon minced into luscious tartare, its pristine quality makes the dish's wink - a Dijon mustard ice cream - all the more effective.

The most memorable course, though, unfolded before us in a multistage presentation that teased several senses. A jam jar filled with a dried porcini, red chile, a bay leaf, and a Japanese orchid petal was covered tableside in warm mushroom dashi and set to steep. Two aromatic minutes later, it was poured like a woodsy tea over a bowl of soy-cured hamachi sashimi. With a "forest" of exotic mushrooms perched like a still life on the bowl's rim for extra-earthy punch, the entire composition was a deeply layered umami bath - but also remarkably light. The sensation that lingered most was still the luxurious snap of the succulent raw fish.

A different pairing with that mushroom forest at my second meal was perfectly good - a big scallop over foie gras sauce with candied pineapple bits. But it was no hamachi, and it pointed to one of Marigold's weak points. The "no menu" tasting isn't quite as spontaneous as it may seem. Halpern works from two basic menu templates, whose specifics change fluidly with seasonality. But the repertoire isn't yet big enough to create especially novel experiences from meal to meal, even separated by a couple of months. Had more specific choices been offered, of course, I could have headed toward less duplication. Diners do get to choose the protein for their entree, but these larger-format plates, although largely fine, also showed room for improvement.

A beautiful sunflower seed-crusted halibut, posed over tomato water dappled with dots of basil, was slightly overcooked. My first night's quail suffered from incoherent overthink, the tiny, fried bird cut into four tinier bits and scattered with different garnishes across a huge plate. Quail No. 2 was more satisfying with a carrot puree, gooseberries, and sweet-potato hash.

My second fish was also memorable, a crisp grouper over surprising lamb tagine studded with chickpeas that was tender and soulful enough to make all the overly precious dots of gel sauces on the side irrelevant. The vegan entree, though, would surely thrill Halpern's former Moosewood colleagues: a tahini-bound quinoa cake sided with chickpea fritters and miso-glazed eggplant.

After a dozen other plates brimming with wit and clever ideas, however, these entrees didn't carry quite the same weight of traditional main courses.

I'd already moved on by the time dessert arrived in a flurry of sweets: a gush of liquefied graham cracker bursting from inside the most delicate chocolate truffle, then a mini-push-pop layered with mousses of white chocolate and foie gras.

And, of course, a fuming beaker of liquid nitro arrived to freeze our bowls of fruit consommé into icy rinks of berry blue. The best part? When the vapor drifted away, and our spoons rested, it felt less like a magic trick than simply a fittingly grand finale to a memorable meal.


Chef-owner Robert Halpern discusses Marigold Kitchen at Inquirer restaurant critic Craig LaBan hosts an online chat at 2 p.m. Tuesdays at