MICHEL GUE'RARD has cooked rich food for the rich. Michel Gue'rard has invented slimming food for the slim. Michel Gue'rard, Southwest France's three-star chef and dreamer of new and ever-newer cuisines, has plans to devise American food for the Americans.

So we asked for a preview. What would a French kitchen visionary dream up for the glorious welcoming of a New Year in an American home?

Gue'rard was traveling around the country demonstrating chocolate mousse as a promotion for his first packaged-for-Americans food: Belgian chocolates. He'd been to New York. He'd been to Chicago. He'd been to Paramus.

"I am the king of chocolate mousse now!" crowed Gue'rard, who is jolly enough to suggest a Santa Claus, but after years of watching his own weight would today be better cast as an elf. He twinkles. Truly. He'd been demonstrating so much chocolate mousse, "I've made it at least as high as the Empire State," he said expansively. He'd even bought a whisk at Macy's which he thereafter carried around the country for mousse making.

How much more American can you get?

When Gue'rard is doing the devising, New Year's Eve dinner naturally starts with caviar. Served how? "Oh. Caviar." That's it. If one insists on detail, "Serve with a spoon."

But this is an American dinner, he remembered. And there are those big American potatoes. So Gue'rard revised his first course: Bake a big potato and cut it in half. Top the halves with sour cream seasoned with a touch of vinegar. Serve caviar on the side, with a very small spoon. Eat the very cold caviar with the warm potato and sour cream by spooning one and then the other. And downing a little American champagne, which Gue'rard says is getting "much more interesting."

Next course, that most American of dishes, lobster. Lobster with cabernet sauvignon and pears was a recipe Gue'rard invented in the Napa Valley, where the vineyards inspired him to juxtapose lobster with the French tradition of pears and red wine. "It's better to have lobster with pears as a main course instead of pears with lobster as a dessert," cracked Gue'rard, who admitted he just may have made one chocolate mousse too many. In any case, the sweetness of the lobster, he explained, lends itself well to other tastes that are sweet. So for this dish he finished his lobster sauce with cre me de cassis and garnished the dish with wine-poached pears. To drink with this, he recommended a strong chardonnay, suggesting that the rest of the cabernet be saved to drink with the main course.

Main course? Doesn't he know about Americans' streamlined meals? No, he would then go on to something "very baroque," he said, muttering about pigeon broth and vinegar and artichoke hearts. But then he latched onto turkey. True, he mused, in America turkey is passe'. On the other hand, it is a holiday staple. So in the U.S. he would concoct a new American tradition, a confit of turkey.

You start two weeks ahead (while you are still in the throes of frantic Christmas activity). Bury the turkey in salt for a day, then wash off the salt and immerse the whole turkey in rendered goose fat or salt-pork fat to cover, seasoned with salt, pepper, bay leaf, rosemary and six cloves of unpeeled garlic. Cover the pot and cook for six hours in an oven just hot enough to keep the fat bubbling slightly and the pan shaking gently as it cooks until a straw can be easily poked through the turkey. Let cool slowly and store in the fat, in the refrigerator, for two weeks while the confit mellows. To serve, remove the turkey from the fat and roast it in a medium oven, 350 degrees, for about an hour until the meat is warmed and the skin is crisped.

He hadn't tried it, he warned. And we wouldn't either, we decided, after spending a little thought on where we might obtain a potful of rendered goose fat.

We did try, however, the potato gratin he suggested to accompany the main course, and found it well worth the outlandishness of having two potato courses. It consisted of saute'ed potatoes, onions and apples layered with apricots, moistened with chicken broth and baked slowly until the broth was absorbed. And it could be made in advance, then reheated.

On to the salad course, a truffle salad. The recipe? "First you find the truffles," chuckled Gue'rard. He then added that if you were going to use canned ones, they must be the ones labeled "first cooking," which means that unlike most canned truffles they had been cooked only once rather than cooked and then sterilized in another can and thus robbed of their flavor. Slice the truffles into 1/8-inch rounds and sprinkle with salt, olive oil and lemon. "That's all." Another impish grin, "And if people don't like truffles, you give them noodles."

For dessert? "Chocolate mousse!" With what to drink? "Eh! Water!" Although on second thought he suggested that even with chocolate one could serve sauternes or port, but only vintage port and definitely served very cold.

Surely he wouldn't face chocolate mousse again for his own New Year's Eve dinner at Eugenie Les Bains, his renowned spa, which is closed in the winter and therefore very quiet. He would, however, have caviar and truffles for New Year's Eve, and probably also a good farm chicken. "I have very simple taste when you don't consider the caviar and truffles." He twinkled again. He always does. MICHEL GUERARD'S NAPA VALLEY LOBSTER (4(4 servings) 4 pears, poached in syrup, or high-quality canned ones 1/2 bottle cabernet sauvignon 4 lobsters, about 1 pound each 4 quarts fish court bouillon (see recipe below) Sauce: 3 tablespoons minced shallots 2 teaspoons butter 1 1/3 cups cabernet sauvignon drained from the pears 1 1/3 cups fish fumet (or substitute 3 parts clam juice simmered with 2 parts white wine and water for 1/2 hour) 7 tablespoons cre me de cassis 7 ounces (1 3/4 sticks) butter Flat parsley and chives, minced, for garnish

To prepare the pears, drain, halve and core them and set aside in a small glass or stainless steel bowl. Bring cabernet sauvignon to a boil, remove from heat and pour over the pears. Let pears macerate for 2 hours.

Melt butter in a skillet and simmer shallots in it very gently, stirring constantly with a wooden spatula, for 3 minutes. Drain 1 1/3 cups red wine from the pears and pour over the shallots. Let reduce to 3/4 its volume. Add fish fumet and let reduce by half. Stir in cre me de cassis. Remove from heat and whisk in 7 tablespoons butter bit by bit. Adjust seasoning. Keep sauce hot while you prepare lobsters.

Cook lobsters in court bouillon for 5 to 6 minutes. Remove from pot, break off the tails and remove the meat from the tails by snipping the translucent shell on the undersides. Break off the claws and remove the meat from them, leaving the claw shells as intact as possible. Set aside tail and claw meat. Remove flesh from the body and reserve for another use. On top of the 4 bodies, make 2 cuts in which you will insert the 2 empty claws, pointing upward.

Serve lobsters on 4 warm plates by decorating the bodies tastefully with their claws, then slice the tail meat and arrange on the shells; arrange the claw meat alongside. You may also simply split the lobsters and serve them with the flesh left in their shells. Coat lobster meat with sauce and sprinkle with chives and chopped parsley. Cut each pear half into 3 slices and place them on both sides of the lobster bodies. FISH COURT BOUILLON (Makes 4 quarts) 6 pounds fish heads, bones and trimmings 4 quarts water 1 bay leaf 1/2 cup chopped carrots 1 cup chopped celery 2 small onions, each stuck with 2 cloves 1 cup vinegar or 2 cups dry white wine 2 teaspoons salt Stems from 1 bunch parsley

Bring 4 quarts water to a boil. Add fish, bay leaf, carrots, celery, onion, vinegar, salt and parsley stems. Reduce heat and simmer uncovered 30 minutes. Strain liquid and use for poaching fish or seafood. REVEILLON POTATO GRATIN (4 servings) 3 medium potatoes, sliced 4 tablespoons butter 2 small apples, sliced 2 medium onions, sliced Pinch of sugar 1-pound can apricots, sliced About 2 3/4 cups chicken broth

In a large skillet saute' potatoes in 2 tablespoons butter until lightly browned. Remove from pan and reserve. In 1 tablespoon butter saute' apples until lightly browned. Remove and reserve. In 1 tablespoon butter saute' sliced onions with a pinch of sugar until very browned. Remove from heat.

Using a shallow baking dish, layer potatoes, apples, onions and apricots. Pour in enough chicken broth to come 1/2 inch above the layers. Bake at 350 degrees for 1 to 2 hours, or until broth has been absorbed. Serve immediately or refrigerate and reheat at serving time. MICHEL GUERARD'S CHOCOLATE MOUSSE (8 servings) 10 ounces chocolate (semi-sweet, milk or white can be used) 2 cups whipping cream 1 to 2 tablespoons liqueur (orange, coffee, cognac, or your choice), optional Orange sections for garnish

Melt chocolate in the top of a double boiler. In a large bowl, using an electric mixer or large whisk, slowly beat 1 cup cream into chocolate until very smooth. Second cup of cream can be added more quickly as you continue whisking. Continue whisking until chocolate cools and cream thickens; it takes a great deal of whisking, but can be speeded up by beating over ice. Beat in liqueur if desired. When the mixture is as thick as whipped cream, refrigerate until serving time. Decorate with orange sections.