"Pack the most valuable things." Bach Ngo's husband gave the order, but, heartbroken over having to leave his home, he went out to the car and waited. Thirty minutes, counting.

It was April 1975, and the United States was evacuating Saigon. Ngo, a pilot, had access to a plane to fly his family out. Frantically, Mrs. Ngo ran upstairs and pulled out a small suitcase. "I put in a lot of recipes. I didn't mean it; it was just my reaction. All my time in Vietnam I was in the kitchen; I love to bake and cook," recalled Mrs. Ngo, who was pregnant with her fourth child when they fled Vietnam. "I don't even remember if I closed the suitcase. We ran. My husband drove to the air base. In the three days (before arriving in the United States) we didn't change our clothes. I forgot to take any for my husband.

"After two years, everything was going quite well," said Mrs. Ngo, settled by that time in Guilford, Conn. "I felt a lot of confidence with the recipes with me."

Enter neighbor Gloria Zimmerman, rice paper in hand, petitioning Mrs. Ngo for lessons on reproducing the delicate cuisine Zimmerman had so enjoyed in France. "All those fresh vegetables, that's what hooked me," said Zimmerman, who first became addicted at the Vietnamese restaurants of Paris.

A collaboration was struck: Zimmerman, a teacher of Chinese cooking, would translate Ngo's techniques to the written page -- ultimately into a cookbood -- as Mrs. Ngo recreated her family's favorite food. "Half or two-thirds of the recipes do not come from the written ones but from my head," said Mrs. Ngo. "They are the ones I cook every day."

For nine months, as Mrs. Ngo cooked, Zimmerman measured and wrote. The resulting book, "The Classic Cuisine of Vietman" (Barron's, $16.95), is "a pretty complete picture of the cuisine of Vietnam, although I have more recipes for two, maybe three books," the Vietnamese woman said.

The task in the first book, however, was to answer the most frequently asked question: How is her country's cooking different from Chinese? "Although we have many of the same staple ingredients as Chinese, we are fond of saying, it's to Chinese as French is to Italian," said Zimmerman, whose use of thef word "we" reveals her close affinity to Vietnam.

"This cuisines is very, very lean, not to worry about the fattening food," added Mrs. Ngo. "In France it is called the nouvelle cuisine orientale. We eat a lot of vegetables raw and barbecue a lot. I have cooked Chinese; in Vietnam we love Chinese food, we go out for Chinese, French -- the Vietnamese people mix them up sometimes. The Chinese are all over my country, but we try to keep our unique cuisine, adapt some ingredients. We use different techniques -- a lot of braising."

Mrs. Ngo was taught cooking by her great-aunt, the third wife of the second-to-last king of Vietnam and an award-winning cook (the award was marriage to the king).

The cooking lessons started when the great-aunt visited the Ngo family home in Nhatrang, on the coast 300 miles from Saigon. Mrs Ngo was nine then. "My family was very, very wealthy. My family was very, very wealthy. My family had 11 children and my mother adopted two more sons," she said.

There are more than 300,000 Vietnamese refugees in the United States. The largest group is in California, followed by Texas and Pennsylvania. In the Ngos' new home town, there are four other Vietnamese families, but other Vietnamese travel from as far as Washington, D.C., to Chez Bach, the restaurant Mrs. Ngo recently opened in Branford, Conn. Customers not acquainted with the cuisine order their way through the menu.

Many of the critical ingredients are now being exported from Thailand, where a lot of Vietnamese have settled, Ngo said. Ingredients are available in oriental speciality shops. There is no substitute for the rice paper, used much like a wonton skin. Similar to a crepe in consistency, it is made from rice, salt and water and left on bamboo mats to dry, giving it a crosshatched pattern. Nor is there a substitute for fish sauce or nuoc mam, the strong liquid made from fermented anchovies that is used alone as a seasoning or as an ingredient in a dipping sauce called nuoc cham. SPRING ROLLS (Makes 80 rolls) For the filling: 2 ounces cellophane noodles, soaked in warm water for 20 minutes, then drained and cut into 1-inch segments 1 pound ground pork 1 large onion, finely chopped 2 tablespoons tree ear fungus, soaked in warm water for 30 minutes, then drained and finely chopped 3 cloves garlic, finely chopped 3 shallots or white part of 3 scallions, finely chopped 7-ounce can crabmeat, cartilage removed and meat flaked with fingers 1/2 teaspoon freshly ground black pepper For the rolls: 20 sheets dried rice papers 4 eggs, well beaten 2 cups peanut oil For the carrot salad: 1 carrot 1/2 cup water 1 teaspoon vinegar Pinch of salt 1 teaspoon sugar To serve: 2 cups soft lettuce leaves 1 cup fresh mint leaves 1 cup fresh coriander 1 cup cucumber, peeled in lengthwise strips with green strips in between, sliced in half lengthwise, then cut in semicircles crosswise Double recipe nuoc cham (see below)

To prepare the filling, combine noodles, pork, onion, fungus, garlic, shallots, crabmeat and black pepper. Set aside.

To prepare rolls, cut a round rice paper sheet into quarters. Place the cut rice paper on a flat surface. With a pastry brush, paint beaten eggs over the entire surface of each of the pieces. Before filling, wait about 2 minutes for the egg mixture to start softening the wrappers. When the wrapper looks soft and transparent, place about 1 teaspoon of filling in the shape of a rectangle near the curved side of the rice paper. Fold the sides over to enclose the filling and continue to roll.

After filling all the wrappers, pour the oil into a large frying pan, put the spring rolls into the cold oil, turn the heat to moderate, and fry for 20 to 30 minutes, until a golden brown.

To prepare carrot salad, first peel carrot. Then, using your peeler, cut long strips of carrot, trying to get as wide a slice as possible, or shred the carrot in a food processor. Roll each strip up tightly and cut roll to make thin strips. Combine the water, vinegar, salt and sugar. Add the carrot strips to the mixture and marinate for at least 15 minutes. Mix 1 tablespoon of the carrot salad into the nuoc cham. This can be prepared ahead.

To serve, place a few lettuce leaves, 2 or 3 mint leaves, some coriander and 2 cucumber slices in a bowl. Top with 2 or 3 spring rolls, sprinkle with nuoc cham. Additional carrot salad may be added to taste. FRIED CHICKEN WITH LEMON GRASS AND RED PEPPER (6 servings) 1 stalk fresh lemon grass or 1 tablespoon dried 4 chicken thighs or legs 2 tablespoons fish sauce (nuoc mam ) 2 teaspoons sugar Sprinkling of freshly ground black pepper 3 cloves garlic, finely chopped 1 tablespoon vegetable oil 1/4 teaspoon cayenne pepper 1 teaspoon caramelized sugar (see recipe below)

If you are using fresh lemon grass, simply discard the outer leaves and the upper 1/4 of the stalk, then chop fine. If you are using dried, it must be soaked in hot water for 2 hours, then drained and chopped fine.

Bone the chicken and cut into 1-inch cubes. Combine 1 tablespoon of the fish sauce, sugar, black peper, 2 cloves of the garlic and the lemon grass. Sprinkle over the chicken and let marinate 30 minutes.

Heat the oil over a high flame and add the remaining chopped garlic, then stir and add the chicken; continue mixing for 5 minutes. Turn the heat down to medium; add the remaining tablespoon of fish sauce, the cayenne pepper and caramelized sugar. Cook, stirring for an additional 15 minutes. Serve with rice. SHRIMP SIMMERED IN FISH SAUCE (4 servings) 1 tablespoon vegetable oil 1clove garlic, chopped 1/2 pound raw shrimp, shelled and deveined, tail section of shell left attached 3 tablespoons fish sauce (nuoc mam ) 4 teaspoons sugar 2 tablespoons caramelized sugar (see recipe below) Sprinkling of freshly ground black pepper

Heat the oil in a small saucepan over a high flame. Add the garlic and stir briefly, then add the shrimp. Turn the heat down to medium and continue to stir as you add the fish sauce, sugar, caramelized sugar and pepper. Cover the saucepan and continue to cook for 3 minutes. Uncover; half the liquid should have evaporated. Serve with rice. BARBECUED BEEF WITH LEMON GRASS AND NOODLES (6 servings) 1 pound lean, boneless top or bottom round beef 2 quarts boiling water 1/2 pound rice sticks or Japanese alimentary paste moodles (somen) 1 cup shredded cucumber 2 cups shredded lettuce 1/4 cup fresh mint leaves, chopped 1/4 cup fresh coriander, chopped 10 roasted peanuts, coarsely chopped 1 fresh or dried hot red chili pepper Shredded whole coriander sprigs for garnish Nuoc cham (see recipe below)

Slice beef 1-inch thick (partially freezing beef makes slicing easier). Preheat oven to 450 degrees. Cover the bottom and sides of a baking pan with aluminum foil. Spread the beef slices over the bottom of the pan, allowing the pieces to touch and overlap (this will prevent meat from drying). Bake for 10 minutes in the center of the oven. Let cool to room temperature.

To cook the rice sticks, bring 2 quarts of water to a boil. Drop in sticks and return to boil for 5 minutes. Drain the sticks in a colander, then rinse under cold water. To cook the somen, bring 2 quarts of water to a boil. Drop in the noodles and boil for 1 minute, then transfer to a colander and rinse under cold water.

To serve, place some of the cucumbers and lettuce in the bottom of each of 6 bowls. Sprinkle of some of the mint and coriander. Distribute the noodles among the bowls. Place the beef on top. Sprinkle with more mint and coriander, plus the peanuts. Add a few pieces of shredded hot pepper on top and decorate with a sprig of coriander. Serve with nuoc cham. NUOC CHAM (Makes 5 tablespoons) 1 clove garlic 1/2 fresh hot red chili pepper or 2 dried 2 heaping teaspoons sugar 1 fresh lime 2 tablespoons fish sauce (nuoc mam ) 2 1/2 teaspoons water, more if necessary

Peel the garlic. Split the chili pepper down the center and remove the seeds and membrane. Cut into pieces and put into a mortar, together with the garlic and sugar. Pound into a paste. Squeeze the lime juice into the paste, then with a small knife, remove the pulp from the lime section and add it as well. Mash this mixture and add the fish sauce and water, adding more water if it is too strong. CARAMELIZED SUGAR (Makes 1/2 cup) 1/2 cup sugar 3/4 cup water 1 teaspoon lemon juice

Put the sugar and 1/4 cup of the water into a dry, 8-inch frying pan over high heat. When the sugar starts to brown, start stirring constantly. When the sugar turns dark brown and you see steam forming, stir well, remove from heat and add the remaining water. Continuing to stir, return to high heat for about 5 minutes. Add the lemon juice, giving a few quick stirs, and remove from the heat. Allow to cool and transfer to a jar.