In 1951, shortly after Jeanne Maynard was married, a dinner guest told her she didn't know how to cook. Of course he put it more diplomatically, asking her if she had the price of a cookbook. But his message was clear.

He volunteered to teach her how and they cooked French food together for their respective families every Saturday for about a year. She became so proficient that eventually she made the pastries for her teacher and his family because she was better at it than he was.

This work as a "caterer" was prophetic. Twenty-six years later Maynard is officially in the catering business. She specializes in Chinese, Vietnamese and Thai food because her family spent many years in the Orient. But her biggest job so far has been a ham, beef and turkey supper for 650 people the night of the Inaugural Concert at the Kennedy Center.

A friend called her "in a panic" because the Inaugural Committee would not use non-union help for any of its activities. The employees of Canteen Corporation, which runs all of the food operations at the Center, are non-union. So Maynard got the job of catering the party; volunteers acted as waiters and bartenders and the crisis was averted.

Maynard began cooking in Vietnam out of necessity. Although she had a cook, he would never buy more food than was sufficient for the family. This precluded Maynard from ever having last-minute company, something she dearly loves to do. So she took over the kitchen chores herself.

She describes Vietnamese food as "more delicately flavored and lighter than Chinese and it usually contains the ubiquitous fish sauce," made from fermented fish and very salty. The sauce is also used in Thai cooking, but not in Chinese. The Vietnamese use more sugar and a lot more chill peppers served on the side than the Chinese.

However, "the distinction between Chinese and Thai cooking," Maynard said, "is a lot more blurred.Thais serve a number of dishes at the same time, but do not use chopsticks like the Chinese.

"In many ways Thai cooking is close to Indian," Maynard explained. "They use a lot of curries and in both countries add hot peppers while cooking. Indian curries, however, aren't as sweet. The Thai use an awful lot palm sugar, which is like brown sugar, and serve a lot of coconut dishes, which are sweet. They also use garlic in nearly everything and plenty of fish sauce."

The most common dish in Thailand is mi grob , a fried noodle creation which is seasoned with crab, pork, chicken, shrimp, garlic, fish sauce and a number of other ingredients. Maynard's grown children like it as well as almost anything and will eat it with almost anything.

The birthday dinner for one of her two children was trout in black butter with mi grob . The other asked for veal cordom bleu and mi grob . "I told them it was tacky," Maynard said with a laugh, "but they didn't care."

Maynard said she has "fantasized about catering for a long time." But less than a year ago she decided to earn a living. "I just sat down one day and said: 'What is it you do best?'" The answer was "cook."

Most of her work, which comes only from word-to-mouth referrals, is for French or Chinese food. "It's funny," she said, "how many people are afraid to make Chinese."

She prefers cooking Asian food for small parties. It is provided at a reasonable price for a catered dinner: $6 a person, excluding beverage.

Cocktail parties are $2.50 to $4.50 per person. She cooks at the home of the person giving the party and charges a flat fee of $10 for doing the grocery shopping if requested. But she perfers buying the ingredients because she knows exactly what she needs.

Maynard and a friend are negotiating for a stall at the Bethesda Farm Woman's Market where she would like to sell Chinese delicacies such as lemon chicken and diet-watchers specials like crustless spinach quiche. In the meantime she can be reached at 565-2167. MENU FOR EIGHT Stuffed Tapioca Balls (Saku sai mooh ) Fat Horses (Ma Von ) Chicken with Ginger (Kai ga Khing on ) Sweet Pork (Mooh wan ) Beef Salad (Yam ) Crisp Noodles (Mi grob ) Rice (Khao ) Batter Fried Bananas (Kluay Khaek ) BEEF SALAD (8 servings as part of Thai meal) 1 pound under-roasted beef, sliced paper thin 1&8 teaspoon dried lemon grass* 5 young makrut leaves, crushed* 10 sprigs coriander, shredded 5 cloves garlic 5 small hot chillis, seeded Pinch black pepper 5 tablespoons sugar 5 tablespoons fish sauce (nam pla )* 3 tablespoons lime (or lemon) juice

Mix beef, lemon-grass makrut leaves and coriander together. Crush together the garlic, chilis, black pepper, sugar, fish sauce and lime juice. And this mixture to the beef mixture and allow to stand a couple of hours before serving. This is best served at room temperature. MI GROB (Serves 8 as part of Thai meal) 3 cups oil for deep frying, approximately. 5 cloves garlic, minced or pressed 6 raw shrimp 1/3 cup raw pork, minced 1/3 cup raw chicken, minced 1/3 cup crab meat 2 tablespoons sugar 1 tablespoon soy sauce 1 tablespoon fish sauce (nam pla )* 1 tablespoon lemon or lime juice 1 tablespoon white vinegar 1 teaspooon cornstarch 1 tablespoon water 1/3 pound Chinese vermicelli 2 eggs, beaten 6 or more pickled green onions* 2 hot chilis, about 4 or 5 inches long, seeded and shredded 1 cup fresh bean sprouts 1 cucumber, peeled and cut into oblongs, 2 inches by 1/4 inch 1 lime cut in eights

In 1 tablespoon hot oil, saute garlic, add shrimp and meats; cook over high heat 1 1/2 to 2 minutes, no longer. Set aside. Mix together sugar, soy sauce, fish sauce, lemon juice and vinegar; stir in mixture of cornstarch and water. Bring to a boil and cook 3 to 4 minutes. Remove from heat.

In a deep pot, heat 3 cups oil. Drop a handful of noodles into hot fat; remove as soon as they puff, which is almost immediately. Drain well on paper towels. When noodles are done, mound on large platter. Dribble beaten eggs from a fork into hot fat remaining in pot. Remove with a slotted spoon when cooked. Place sauce over heat, add meats and heat through; pour over noodles. Decorate with fried egg, green onions, chilis, bean sprouts and cucumber. Serve each person with slice of lime to be squeezed over. SWEET PORK (Serves 8 as part of Thail meal) 1 pound pork tenderloin, cut inot bite-size pieces 4 spring onions, cut small 2 tablespoons peanut oil 1/2 cup brown sugar 1/2 cup fish sauce (nam pla )* Dash pepper Water to cover

Saute meat and onions in oil. Add sugar, fish sauce, pepper and water and cook about 2 hours, or until tender. Then remove cover and boil until only a dark, sryupy liquid remains. Serve with rice. Good reheated next day. CHICKEN WITH GINGER (Serves 8 part as Thai meal) 1/2 cup black jelly mushrooms* 4 spring onions, cut small 3 tablespoons lard 3 cloves garlic, minced or pressed 1 tablespoon light soy sauce 3 tablespoons shredded fresh ginger 3/4 cup boned raw chicken, cut into bite-size pieces 1 tablespoon vinegar 1 tablespoon or more fish sauce (nam pla )* 1 1/2 teaspoons sugar Fresh coriander leaves

Bring water to boil, add mushrooms; turns off heat and soak mushrooms for 1/2 hours. When soft, trim and wash well.

Saute onion in lard, and garlic, soy sauce, ginger and chicken; stir-fry about 2 minutes over high heat. Add drained, but moist, mushrooms. Mix together vinegar, fish sauce and sugar and add to chicken mixture. Serve hot decorated with coriander leaves. FAT HORSES (Serves 8 as part as Thai meal) 1/2 cup unsalted fat back 1/2 cup raw chicken meat 1/2 cup cooked crab meat 1/2 cup minced or ground lean pork 3 coriander roots Pinch pepper 1 tablespoon minced or pressed garlic 2 tablespoons fish sauce (nam pla )* 2 tablespoons brown sugar 2 tablespoons coconut cream* 2 eggs Fresh coriander leaves 1 teaspoon minced green onion

Chop the meats and pork fat together until very fine. Pound coriander roots, pepper and garlic until a paste is formed; mix with meats, seasonings and coconut cream. Beat eggs until foamy, having reserved half of one yolk. Mix eggs and meat mixture. Heap into demitasse cups (or into empty 3 1/2-ounce jars or cups fashioned from foil wrap about 2 3/4 inches in diameter and 2 inches deep). Brush tops of mixture with reserved half yolk, beaten. Sprinkle with coriander leaves and green onions. Steam over boiling water about 30 minutes. When cool remove from cups and serve.

Available at The Thai Room, 5037 Conn. Ave. NW; Mikado, 4709 Wisconsin Ave. NW; Fumie Oriental Mart, 11301 Grandview Ave., Wheaton.