Abalone makes a dramatic impression at Mirabelle. (Deb Lindsey/For The Washington Post)

The most moving dish downtown right now is the abalone appetizer at Mirabelle. Diners who order this taste of the Pacific, served as a chopped seafood salad in its iridescent shell on enough seaweed to carpet a studio apartment, are treated to a spectacle when a server pours water onto the green backdrop. Hidden in the mound of seaweed are dry ice and lemon grass oil. You don’t have to be a chemist to imagine what happens next. A white fog wafts up and across the table, accompanied by the spicy perfume of the tropical grass. Once the cloud dissipates, and the scent mellows, you try the grilled, scored abalone, tossed with black Chinese vinegar and yuzu juice, and continue to smile.

The dish, garnished with a ginger-coconut foam, does exactly what its creator intends. “For a split second,” says Keith Bombaugh, Mirabelle’s chef since late July, “we want to take you outside the dining room.”

The drama before the drama, of course, is the story of Mirabelle, which opened with sky-high expectations two springs ago, with former White House chef Frank Ruta in the kitchen, veteran wine maven Jennifer Knowles overseeing liquids and service, and a handsome dining room, courtesy of restaurateur Hakan Ilhan, who poured more than $3 million, wine inventory included, into the corner of 16th and K streets.

Early visits encouraged repeat reservations. But friction between the chef and general manager resulted in Knowles’s departure in September 2017, followed by a curious dip in the execution and delivery of Ruta’s menu. Business dropped. Food costs ran high. When Knowles met with Ilhan to propose taking over the restaurant with another chef, Ruta’s fate was sealed, and he was let go, along with pastry chef Aggie Chin, in mid-July.

Executive chef Keith Bombaugh. (Deb Lindsey/For The Washington Post)

Duo of lamb. (Deb Lindsey/For The Washington Post)

I know, I know, it’s a lot to digest. But it needs to be told, because if you’re going into 2.0 thinking it’s going to taste like the original, you’ll be in for some surprises, some good, some less so. The dining room hasn’t been touched. It’s still easy on the eyes, if a little louder than in the Ruta era, thanks to a busier bar, manned once again by Zach Faden. The cocktail enthusiast makes, among other treats, a Pommeau J’Adore whose snap conjures a walk in the woods on a brisk autumn day.

Bombaugh, 29, comes to Washington via Boston, where he last worked at Meritage in the Boston Harbor Hotel. He brings some impressive credentials, having learned the ropes from two big industry names, Barbara Lynch of Menton in Boston and Grant Achatz of Alinea in Chicago. His food at Mirabelle speaks to the classical as well as the daring and can be experienced a la carte or as multiple tasting options, from as few as four courses to as many as a dozen.

Meals are sprinkled with nice gestures. “Would you like a black or white napkin?” your server will ask. Mirabelle’s hot rolls are trumped by their choice of spreads, including snow-white whipped lardo (pork fat) and butter sharpened with ramps.

The amuse bouche is a bust, however. Bombaugh reimagines peanut butter and jelly as a peanut-dusted Concord grape sphere in a shot glass of toasted brioche broth. (Roll that around in your mind for a moment. Or not.) Instead of whetting a diner’s appetite for more, the gift from the chef makes a guest anxious about what’s ahead.

Burgundian truffle tagliatelle. (Deb Lindsey/For The Washington Post)

The dish I could order every visit, if only my conscience allowed, is housemade tagliatelle. The pasta embraces some of my favorite flavors in its Parmesan cream, hazelnut garnish and filings of black truffles from Burgundy. A tweet would include #decadent. A close second is a duo of lamb — pink loin and crisp belly — that looks to Greece with its streak of cherry gastrique and “moussaka” brunoise.

“He can cook,” I whisper to my dining companion one night, the memory of that abalone and the tagliatelle lingering in my mind.

“Yes, but it’s not necessarily what we want to eat,” comes the reply from a man who leaves unfinished a first course of crab in a porridge of sherry-flavored “pearls” and Old Bay-seasoned pine nuts strewn with thin semicircles of celery.

Bombaugh grew up on Cape Cod, where some of his fondest memories involve fishing with his father, grandfather and brother, scaling their catch in the water and cooking it on a live fire. Hence “Memories of Ice Pond,” a $19 first course staged with chunks of charred trout, smokier cucumber and a pale green puree of shishito peppers and Japanese pickled plums. Loath as I am to dismiss anyone’s good old days, the story doesn’t translate well to a fancy restaurant. The chef wants us to see the plate as if it were the bottom of a pond. Unfortunately, we do.

The lunch menu promises a “Moroccan spiced” chicken that is ceremoniously presented in a fanciful tagine, which turns out to be the most interesting part of the order. The sliced chicken, arranged with artichokes and baby carrots on red wheat berries and chickpeas, is so faint in flavor, I can’t help but wonder if someone forgot to season it before it left the kitchen. If it’s fowl you want, quail stuffed with mustard greens, their bitterness a nice foil to the rich bird, is the way to fly.

Saturday-night diners at Mirabelle. (Deb Lindsey/For The Washington Post)

Some trimming here and there might nudge a few ideas from the realm of the strange to the sublime. A “risotto” of long-simmered wheat berries paved with a forager’s dream of sauteed mushrooms would be a better dish without the green tufts of tarragon “moss” that have the texture of angel food cake. And ruddy venison on a ragout of beluga lentils is a hearty fall entree garnished with “leaves” of dehydrated shiso, sweet potato and other things, as well as an unfortunate merlot “veil” that smacks of fruit leather for the 21-and-older set. The quote marks are more Mirabelle’s than mine. Think of them as yield signs. The lobster “roll,” offered at lunch, is cheffy but also luscious: puff pastry filled with chopped seafood and rich herbed cream.

Pastry chef Zoe Ezrailson left shortly before this review went to press. I’ll miss her elegant beehive that tasted like lemon meringue pie. For the moment, I can vouch for the autumnal Calvados-spiked apples and caramel mousse layered in a little glass jar, and the one-bite Boston cream pies dropped off ahead of the check.

Service is, for the most part, correct and cordial, although diners might be tempted to shoo away staff who feel compelled to ask for a report card for every dish or snatch a plate the moment the last bite is dispatched. Knowles is a chatty presence in the dining room, and if you show the least bit of interest in what goes into your glass, the onetime sommelier at the Inn at Little Washington is a talking Wikipedia. (That’s a compliment.) Get her started on Chilean wines, her current fascination, and she’s off to the races.

Four months into its reboot, Mirabelle is still finding its way. Risks and rewards are about equal. The best strategy at the moment is to focus on the more straightforward dishes, think carefully about what gets quoted, and drink up.

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Mirabelle  (Good) 900 16th St. NW. 202-506-3833. mirabelledc.com.

Open: Lunch Monday through Friday, dinner Monday through Saturday. Prices: dinner appetizers $16 to $24, main courses $29 to $39.
Tasting menus from four courses ($85) to 12 courses ($195). Sound check: 74 decibels / Must speak with raised voice.