What do people talk about in restaurants? Other restaurants. That's what Joe Baum has discovered as he listens to the buzz at Aurora, the luxurious new restaurant he opened in Manhattan a couple of months ago.

Creator of several of New York's most reknowned restaurants, including the Four Seasons, Forum of the Twelve Caesars and La Fonda del Sol, Baum has not operated a restaurant since he opened Windows on the World, and as he is learning, the restaurant business has changed.

"There is a big difference between being a candle in the darkness . . . " said Baum, leaving the thought to complete itself while he looked around his restaurant, nearly empty on a holiday lunchtime. There is a lot more competition now. Peoples' expectations are higher. Diners have traveled, they know more about what they are eating. It is harder to surprise them.

It is also necessary now to cater to special interests. Each evening the kitchen gets three or four requests for dishes with no salt, and in general chef Gerard Pangaud, hired away from his own two-star Parisian restaurant, had been cutting back from the amount of salt he would have used in France.

Another new factor in American restaurants is "the aggressive non-smoker," said Baum, who has horror stories to tell of trying to pacify smokers and non-smokers alike. What Baum intended was for Aurora to be the ideal version of an elegant bar restaurant, a recreation of the relaxed, comfortable but grand dining rooms we associated with James Beard and Lucius Beebe. It was to be "a restaurant for grownups," continued Baum, where you could be private and public at the same time. He spent nearly two years planning the restaurant with Pangaud, designer Milton Glaser and architect Philip George. And the result is a dining room both seriously luxurious and lighthearted, with glove-leather banquettes and ceiling lamps that look like giant pink champagne bubbles. Since nowadays both men and women go to such grownup restaurants in more or less equal numbers, the restaurant was designed to look both masculine and feminine, said Baum. People eat differently than they did when Baum opened his last restaurant, and they eat differently than do Parisians, Pangaud discovered. In New York peole eat more grilled food at lunch; about 80 percent of the lunch orders are grills, while in Paris very few would be. And people eat faster. Pangaud shook his head as he calculated that he is expected to serve three courses in less than an hour and a half. He also learned that rare, medium and well done have different meanings here than in France; Americans expect each to be more cooked than a Frenchman would. Chimed in Baum, nowadays diners are specifying whether they want their fish and veal done rare, medium or well done, which they never did before.

And then there is that lightness. Some people equate lightness with coldness, and so at Aurora they order cold plates even in winter, said Baum. Light or not, potatoes are popular in America, found Pangaud. He serves potatoes with everything from sweetbreads to pigeon. He is also using ingredients he had never used in France -- radishes, and horseradish (as a crusty topping for salmon). What Americans don't eat are aspics or confits -- those meltingly rich ducks preserved in their own fat. With encouragement, though, diners are learning, and the confit is becoming popular at Aurora after all.

It is definitely harder to make money in the restaurant business nowadays, said Baum. Startup costs are tremendous, and there are many more ambitious restaurants competing for the same dollar. It is commonplace now for restaurants to make their own ice creams and sherbets daily; it is harder to impress customers. And with an average check of $70 at dinner, and prices such as $19.50 for one-fourth of the appetizers, main dishes running around $30, Aurora needs to impress in order to fill its 125 seats.

Which brings Baum to another difficulty: Criticism is more ready. New York Magazine critic Gael Greene was there the first week, and by the first week in January was already in print with, "Aurora is still shaky all over." Even weeks after that, I found shakiness an understatement. The waiter introduced himself with, "Hi, my name is Tony" (which made Baum cringe when he heard of it) and never once poured our wine after the first glass. Asparagus timbale tasted flat under its wonderful blanket of black chanterelles and white truffles; crepinette of pheasant was overcooked and dry; there was a computer mixup with the bill. It takes three or four months for a restaurant to develop, said Baum. Waiters need to learn to anticipate diners' needs, and to always perform some service when they approach a table. They must be trained never to interrupt or to ask a question that requires an answer, such as, "How is everything?" Pangaud is aiming for a menu that he can control, preferring to be "constant rather than brilliant." The crepinette of pheasant, he has realized, is difficult because it is stuffed, and you can't tell what the texture is inside when it is cooking; furthermore, it is a texture that is unfamiliar to most of his cooks, who are American. The sweetbreads, cut into scallops and saute'ed until they are crusty, are attractive to serve, easy to control in the cooking and easy to eat -- and they are very popular. So is the game consomme' served as an intermezzo between the appetizer and main course as other restaurants serve a sorbet; it is becoming Aurora's signature.

By the end of January The New York Times was declaring Aurora a success. But even before that Baum was taking his heavy competition philosophically, stating, "I'm happy to live in times like these. It's like an architect living when buildings were being built." Tabletalk

The Academy Awards for cookbooks are alive once again. On the heels of the demise of the commercially sponsored Tastemaker Awards, the International Association of Cooking Professionals is instituting annual cookbook awards, the first of them to be announced in 1987 for books published in 1985 and 1986.

Most New York restaurant guidebooks are so hefty they could double as weapons. So the pocket-size "Passport to New York Restaurants," by John Mariani and Peter Meltzer, would be a welcome change even if it weren't so comprehensive, efficient and reliable. Two hundred and seventy five restaurants fitting into your vest pocket make a bargain at $5.50. Write for a Passport guide to 967 Lexington Ave., Suite 115, New York, N.Y. 10021.

There's chili, and there's Cincinnati chili, and nobody would confuse the two. Cincinnati chili tastes vaguely Greek, since it is seasoned with cinnamon; and it looks vaguely Italian, since it served over spaghetti. And it is going national, as Cincinnati's Gold Star Chili Inc. expands to Chicago, Indianapolis, Louisville, St. Louis, White Plains, N.Y., Orlando, Fla., Pensacola, Fla., and New York City. It's not tackling Texas -- yet. MADELEINE KAMMAN'S TIMBALES OF ASPARAGUS WITH ONION CREAM (6 servings)

If you are looking for an asparagus timbale to make at home, this one takes advantage of the flavor of asparagus to make a first-course with a fresh and intriguing flavor.

2 pounds medium asparagus

3 tablespoons butter

1 tablespoon cornstarch

1 cup whipping cream

4 eggs

1 teaspoon ground coriander

Salt and freshly grated pepper to taste

FOR THE SAUCE:

2 tablespoons butter

1 strip of orange rind, 2-by- 1/2-inch

1 onion, sliced very thin

1 1/2 tablespoons cider vinegar

1 cup whipping cream

Reserved asparagus tips

ld,10 sw,-3 sk,3 To prepare the timbales, peel asparagus; cut off tips and blanch them 3 to 4 minutes in boiling salted water. Drain and reserve for the sauce. Cut asparagus stems into 2-inch long chunks and blanch for 2 minutes.

Heat 1 tablespoon of the butter in a skillet. Add the asparagus stems and cook until tender, or another 5 to 6 minutes.

Pure'e in the blender together with the cornstarch, cream, and eggs. Add coriander, salt, and pepper to taste and process again for 1 minute to blend well.

Butter 6 custard cups with the remaining 2 tablespoons of butter and ladle the custard mixture into the cups. Bake in a hot water bath at 325 degrees until a skewer comes out clean, 20 to 25 minutes.

While the custards bake, prepare the sauce. Melt the butter in a sauce pan. Add the orange rind and let stand for 1 minute. Discard the rind. Add the onion and cook until golden. Add the vinegar and cook until completely evaporated. Add the cream and reduce to coating texture (approximately 2/3 cup). Correct the seasoning and strain the onion out. Add the reserved asparagus tips and reheat well.

From "In Madeleine's Kitchen," by Madeleine Kamman, (Atheneum, New York, 1984)