Twenty days from now, raviolis a` la pure'e de betteraves rouges au caviar, beurre de ciboulette (pale pink beet ravioli with black caviar in a green-flecked ivory chive-butter sauce) will disappear as one of Washington's gastronomic monuments. The other shoe has dropped at Le Pavillon. After filing for bankruptcy in August and trying to reorganize to continue operating, the restaurant will close its doors with a farewell party, probably Dec. 17, then a final dinner for La Chaine des Rotisseurs, the elite wine and food society, on Dec. 18.

Yannick Cam -- introduced to Washington in 1979 as "the $100,000 chef" -- and his partner Janet Lai Cam will leave Washington, dissolving their celebrated restaurant and their marriage.

Thus will end one of Washington's most extraordinary restaurants ever. Le Pavillon, first housed in a K Street basement, and since 1983 in one of the city's most glittery and visible locations overlooking Connecticut and L streets, has led the avant-garde in French cooking here.

It was the first local restaurant whose menu was devoted exclusively to nouvelle cuisine, and for a decade it shared with Jean-Louis of the Watergate the city's top honors (as well as its top prices). Yannick Cam introduced the city to white chocolate mousse. His gateau of crab, his tourte de foie gras, his chestnut mousse and his galette au citron have been mimicked on restaurant menus from Alexandria to Paris. "They are all over town," said Yannick.

Now the Lalique table just inside the dining room -- valued at $55,000, according to Janet Cam -- and the award-winning wine cellar are to be sold, along with the Haviland china and European crystal. No longer will the sterling egg cups hold Cam's brandade of sole with lobster coral and caviar.

Yannick is choosing among job offers from hotels in Singapore, Taipei, Hong Kong, Seoul and Toronto. Janet is heading for Los Angeles, to establish a home for their son Austin, born one month before the new restaurant opened in 1983, and to find a job in the wine and food field. They have been secretly separated since the summer, but have continued to operate the restaurant together -- more compatibly than ever, they both agreed.

The final decision on closing the restaurant was made at 2 Monday afternoon, and that evening they reminisced at a corner table in Le Pavillon, with Yannick running back and forth to the kitchen to prepare his first six-course farewell dinner.

"It's been fabulous," said Janet, who wore a sexy black dress that was the fashion equivalent of Yannick's homard ro~ti aux betteraves rouges. And she smiled through the first couple of glasses of Krug champagne. Smiling in public: "That's what the obligation is," she said.

It's been an era of taking reservations from I.M. Pei himself, of Madonna's secret first dinner in Washington. "Nobody ever knew," confided Cam. "Privacy was always acknowledged here." She pointed to Table 25, where Nancy Reagan had "all her interviews with Time magazine" and -- contrary to myth -- "always ate what she ordered," including her favorite dessert, the galette with lemon curd and strawberry coulis.

Le Pavillon could boast of serving no presidents, but "it was lords, barons" and one emperor-to-be. "We took care of them and made sure they were protected," she said of her customers. "We knew their allergies. We knew their conflicts of interest." Le Pavillon was "where the real business was done," she boasted.

Monday, with a third of the tables filled and a couple nuzzling in the opposite corner, and after a few nibbles of velvety, coriander-scented salmon in a kind of rice-paper spring roll, Janet began to get teary. "The sad part for me is, it's the last time Yannick will cook in the United States."

Despite having rung up dinner checks as high as $4,000 a couple (which included a $2,500 magnum of '45 Mouton-Rothschild and a tip of more than $800), Le Pavillon hasn't given Yannick all the scope he's craved. "I have never been able to use more than 30 or 40 percent of my capability," he said, because he could never afford the necessary kitchen brigade of 10 or more, or a sufficiently consistent and receptive customer base to do all he wanted. "For the Japanese we have always been more adventurous," he revealed. "The most interesting dinners were served to Japanese."

Until 1987 the restaurant did well -- in fact, it was a smash hit. But after the stock market crash that year, things began to slide. Tax laws changed, so that his expensive meals were not fully deductible. More recently restrictions on entertaining of government officials have further hurt Le Pavillon's business. "Slowly the decisions were made by the government. ... We were the victim of the changes," complained Yannick. Support by customers declined; convention business dried up.

Gross revenue slipped from a norm of $1.8 million a year to barely more than $1.2 million last year. "This kind of restaurant needs $2 million," said Yannick. That's $6,000 in sales, six days a week. Business became too irregular -- 30 diners one night, six the next, 60 the day after. Some lunchtimes they served only one table, then in October 1989 they had a record month. Slowly suburban restaurants siphoned off weekend customers who had once dined downtown.

The decline fed on itself and picked up speed. "When customers go to a restaurant that's three-quarters empty, they have fear that they chose the wrong restaurant," explained Yannick.

It all took a toll on Yannick's cuisine. "When you start to worry about all of these things, you cannot cook," he confessed.

Though the customer base was shrinking and the restaurant cut back on staff, Le Pavillon couldn't drastically cut expenses. "Our customers still want caviar and foie gras," said Janet. Added Yannick, "This is the first year I was not able to use white truffles. We used to use 1 to 1 1/2 kilos a week."

Not only was Le Pavillon a child of the Reagan era that had to face the comeuppance of the late-'80s downturn, but the restaurant also suffered from having a reticent chef in an era of kitchen celebrities. Yannick was never good at making the rounds and schmoozing with customers. "In France, three-star chefs come out, but the brigade is 16," Janet said in his excuse. Still, she admitted, "he never wanted to be in the limelight." Yannick didn't often get his picture in magazines (though it is in this month's Esquire) and rarely made public appearances at charity galas. He did, however, train chefs who went on to work in such celebrated kitchens as the Quilted Giraffe and Bice in New York, Jordan's in Leesburg, D'Artagnan in New Hampshire and Galileo here.

And Le Pavillon's wine list was famous. "We bought early, and we both knew wine," said Janet, whose appetite had returned with the arrival of the tiny fresh snails with potatoes and bacon in chive fumet. "We were the first restaurant to make a great burgundy commitment." When Yannick sent an '85 Echezaux to the table, thereby having read her mind as to the wine she craved, her spirits picked up more, and she attacked the lobster salad with batons of turnip and julienned truffle with enthusiasm.

"We ran it like a three-star," she said of their restaurant. She described the process of installing the hand-tinted Italian wallpaper to dovetail rather than overlap and to achieve the "canestone effect" of intentionally mismatched sections. The restaurant cost roughly a million dollars to furbish, and there was no stinting on the china, the crystal or the French silver. "We're the only restaurant in Europe or here to have this quality silver," she said, then described her efforts to protect it from souvenir-hunting customers.

The duck with Jerez vinegar sauce and endive confit emboldened her more. "This is a restaurant where the tables don't turn. In what restaurant does that exist anymore?" she asked rhetorically. "This was an art form without compromise. It was in its purest form. ... We wanted to be the last bastion of civilization."

Yannick reappeared when he finished cooking the lamb. Seen as a private person, Yannick has never been known as loquacious. But when he gets talking about food, he becomes animated.

He reminisced about his "gateau" of lamb brains, a very, very light mousse with a center of lamb brains, wrapped in white truffles and baked slowly in a water bath until it releases a little juice "so the flan is on a little consomme of its own." He stirred with his hands as he described his civet of lobster and tiny squid with its rich sauce of vermouth, red wine, anchovy and tomato -- with cloves of garlic to cut the richness. "You mix very hard, and suddenly the dish tastes completely different ... and clear ... and so sharp." He told of testing new chefs on his poached foie gras -- "very simple but so difficult to exercise properly." With such a dish, he instructed, "if you want to serve to a party of 10, it takes five cooks."

He related his finding the right ingredient to lighten and smooth his chestnut sorbet: reduced sauternes. And then he told of the dessert to come, poached pears and his own candied chestnuts in a sauce made with '83 Alsatian Grains Nobles wine, a dessert wine that sells for $200 a bottle. He had bought a half dozen bottles, but "we never sold a bottle, so I thought, the hell with it, I'm going to reduce it." Thus he boiled it down into pear syrup.

The two got giddy when asked about Yannick's most outrageous dishes. Yannick had once reduced a bottle of fabled Petrus wine for a sauce. And when he found out at the last minute that he had to take a dish to a potluck dinner, he bought a Sara Lee poundcake and topped it with brown sugar, fresh peaches and a sauce made from '76 Chateau d'Yquem.

They remember every vintage that went into every dish.

And they both worry that the era of fine dining is at an end. Said Janet, "There's good dining -- but fine dining, that's another matter." Said Yannick, "People aren't willing to spend more than 1 1/2 hours" dining. What's worse, "They are in a rush to eat, then they stay two hours" after dinner.

And he grew more pensive, talking about the closing. He finds it difficult to accept. "You're throwing 10 or 12 years of your life down the drain. ... It's one-third of your career." He admitted that for months he has had difficulty sleeping. And he has been hurt by fans who have abandoned him. "People want to see this kind of restaurant fail." He blames the bankruptcy on circumstances. "I'm not closing because I failed to cook."

And Janet adds, "In the arts there must be a patron."

Still, both admit there is relief in the decision having been made. "I feel better now, knowing that I'm closing," said Yannick.

He expects a lot of other restaurants to follow suit by the end of the winter. Maybe only one will survive among the grand restaurants. "Jean-Louis has that corporate umbrella. Soon there will be only restaurants that are corporately owned." Yannick Cam is looking for an umbrella.