BECAUSE Singapore's Nonya cooking evolved during an age when most men had two wives who could share in the complex preparations, it hasn't exactly caught on with the Instant Breakfast crowd. Many dishes demand a dedication of time and energy that few cooks in contemporary Singapore can muster.

Enter Terry Tan. He learned Nonya's mysteries at his mother's wok, and his great passion is to see that the little-known blend of Chinese and Malaysian cooking survives.

Tan, one of the few cooks in Singapore who specializes in this fascinating and little-known blend of Chinese and Malaysian cooking, became alarmed recently at the influx of convenience foods on the island. They have been replacing traditional dishes at such a startling rate that he feared the complex repertoire of Nonya dishes was in danger of disappearing altogether. So Tan began offering Nonya cooking lessons. Because he is so successful at demystifying the cuisine, his classes are always filled to overflowing.

Nonya cooking has been aptly labeled the food of love, not only because it requires a certain degree of dedication to produce, but because the cuisine combines the cooking styles of Malaysian women and Chinese men. According to Tan, during the 17th century Chinese traders began arriving in Malacca on the west coast of the Malay Peninsula. Many stayed and married into Malaysian families, creating what is now known as a Straits Chinese culture. When daughters were born of these marriages, they were called "nonyas" in Baby Malay, the local dialect.

During the 19th century, many Straits Chinese moved to Singapore--among them Terry Tan's ancestors. Tan vividly recalls watching his grandmother, very much a traditional Nonya cook: "Though her kitchen was cramped, there was a large adjoining area where her favorite grinding implements stood. Her batu qiling was a large slab of hewn granite and the roller needed much strength to be lifted. She would use this to grind a lot of spices when there were meals to be cooked for 20 people, but used her smaller pestle and mortar when cooking a smaller amount. Whatever she cooked was always mouthwatering."

But Tan's mother was his greatest mentor. When he was 10, his father died and the family was forced to take in boarders. His older sisters all married, and the task of helping out in the kitchen fell on Tan's shoulders.

"My mother's kitchen was the best of schools," he recalls. "She was illiterate, but had at least a thousand recipes for Nonya dishes down pat in her head. She cooked by taste and feel, the best way.

"I hated being in the kitchen then," he says. "I was young and wanted to be outside playing with my friends, so I could never seem to remember any of her cooking instructions. Finally, out of desperation, I began scribbling down the recipes. Before I was 14, I had collected the instructions for 500 dishes." It is this legacy of recipes and those long years of on-the-job training that make Tan's school such a success.

The recipes in Tan's recently published "Straits Chinese Cookbook" demonstrate how the Nonya kitchen distinguishes itself from other forms of Chinese cooking. The most startling difference is the predominant use of coconut milk as a cooking medium, an obvious contribution of the Malays. Recipes call for a wide range of vegetables, meats, and seafood stewed in coconut milk with a seasoning paste called belacan, one of the most ubiquitous flavorings in Nonya cooking.

Other Malaysian-inspired dishes are the satays and the sambals common to the Straits Chinese kitchen. Satays, which quickly become a much-talked-about favorite of passengers on Singapore Airlines, are made by marinating pieces of chicken, meat, or shrimp in rempah. The pieces are then skewered and, while being grilled, are brushed with a bruised stalk of lemon grass that has been dipped in oil. Satays are usually served with chopped cucumber and onion and a tangy peanut-based sauce, spiced with chili peppers and flavored with belacan.

Sambals, according to Terry Tan, are "co-stars to the main dishes." This panoply of condiments and dipping sauces is one of the prides of the Nonya kitchen and each cook takes care to see that the balance of flavors is always perfect. Sambals act as counterpoints to the main dishes of the meal, explains Tan. "The principle remains constant: a sharp or tart sambal to counteract an oily soup; a crunchy fried Lkan billis (anchovies) to balance rich nasi lemak (coconut rice.)"

The best of Nonya sambals, says Tan, is acar. It is a spicy, tart and sweet compote of cucumber, carrot, cabbage, onions, cauliflower, garlic, and fat green chilies stuffed with grated papays and sesame seeds.

For festive occasions, the Nonyas produce a startling array of colorful desserts called kuih kuih. Appearance was always of optimum importance, and Tan remembers an aunt who would bring along several varieties of kuih, neatly wrapped in large batik squares, and ask his family's opinion of them. "But how can we offer our opinion if you won't let us taste them?" the aunt was asked, to which she replied, "No, no, you cannot eat. Just tell me the color and smell are perfect."

Nonya desserts are often glutinous and pudding-like, molded into rectangles and then cut neatly into slices. Such desserts are usually made with tapioca, sago flour, glutinous rice, or starchy vegetables such as sweet potatoes. Palm sugar is used for sweetener and coconut for flavoring. The long, thin leaves of the pandan (screw pine) tree are often boiled with the mixture for their delicate, delicious fragrance.

Terry Tan's cookbook is available through Hippocrene Books, 171 Madison Avenue, New York, N.Y. 10016. Further information on the cooking classes in Singapore, all conducted in English, may be obtained by writing to Terry Tan, c/o Times Periodicals PTE, 422 Thomson Road, Singapore 1129.

Although many of the recipes in the cookbook call for ingredients not readily available in this part of the world, here are a few dishes from the Nonya repertoire which can quite easily be prepared in the western kitchen. Macadamia nuts have been substituted for candlenuts, and crushed red pepper or hot pepper sauce replace the wide range of red and green chilies used in Nonya cooking. SOYBEAN CAKES STUFFED WITH SPICY MINCED PORK (6 to 8 servings)

Serve these stuffed bean-curd cakes with peeled, sliced cucumbers and a dipping sauce called chili padi with lime (see below). 8 firm-style soybean cakes (bean curd), each about 3 inches square 3 macadamia nuts 1/2 teaspoon chili powder 3/4 teaspoon aniseed 1/2 teaspoon cumin seeds 1 1/2 teaspoons coriander seeds 5 large shallots, peeled and very finely minced 1/4 teaspoon shrimp paste (available in oriental groceries) 5 tablespoons vegetable oil, approximately 1 large egg, lightly beaten 1/2 teaspoon salt 1/4 pound ground pork

For the sauce: 2 tablespoons dark soy sauce 1 1/2 teaspoons sugar Grated rind and juice of 1 lime Hot pepper sauce to taste

Cut each soybean cake on the diagonal to create 2 triangles. Make an incision about 1/2-inch deep and 1/4-inch thick down the broadest side of each triangle and scoop out the bean curd to make a pocket. (This excess bean curd is delicious when mashed into egg and tuna salad.) Set aside.

To make a rempah paste, grind the nuts with the spices in a spice mortar and pestle. Blend in the shallots and shrimp paste. Heat 2 tablespoons of oil in a small skillet and fry the paste for 2 minutes, stirring constantly. Combine this mixture with the egg, salt, and ground pork.

Stuff each soybean cake triangle with about 1 to 2 teaspoons of the pork mixture. Place in a steamer or on a rack in a large saucepan over about an inch of water and steam the cakes for 10 minutes. Remove from steamer and cool. Heat the remaining oil to a depth of about 1/4 inch in a large skillet. Fry the cakes over medium-high heat until light golden on each side, about 4 to 5 minutes. Drain on paper towels. Serve hot.

To prepare the sauce, combine the ingredients in a small bowl. Set in the middle of the table for dipping. CHICKEN KURMAH (6 servings)

Nonya cooking reflects a certain amount of Indian influence, as the spice blend in this recipe suggests. 2 1/2 cups coconut milk (see recipe below) 3 tablespoons (about 15) macadamia nuts, ground or pounded to a paste plus 1 tablespoon (about 5) additional macadamia nuts 3 tablespoons lime juice 2 tablespoons coriander seeds 1 tablespoon cumin seeds 1 tablespoon aniseed 1 teaspoon whole peppercorns 2 small cloves garlic, very finely minced 4 tablespoons clarified butter (or 2 tablespoons each butter and oil) 6 large shallots, peeled and thinly sliced 1/2 teaspoon finely minced ginger 1 cinnamon stick, broken in two 2 cardamom pods, gently crushed 3 whole cloves 2 to 3 slivers dried lemon grass (or substitute 1/4 teaspoon each crushed red pepper and grated lemon peel) 3 1/2 pound chicken, cut into 8 to 10 pieces 3 large potatoes, peeled and cut into eighths Salt to taste

In a pitcher, combine the coconut milk with the macadamia-nut paste and lime juice. Set aside.

To make the rempah paste, grind the additional nuts, coriander, cumin, aniseed and peppercorns into a paste in a spice grinder or mortar and pestle. Blend in the garlic.

In a large saucepan, heat the butter. Saute the shallots with the ginger, cinnamon, cardamom, cloves and lemon grass for 1 minute, stirring continuously. Add the rempah paste and stir to blend. Cook over medium heat for 2 minutes, stirring constantly. Add the chicken pieces and fry for 2 minutes on each side. Then add the potatoes and reserved coconut-milk mixture and salt to taste. Bring to a boil, then reduce heat and cover. Simmer for about 30 minutes, or until chicken and potatoes are tender. Adjust seasonings and remove whole spices, if desired. NONYA HOT VEGETABLE CURRY (4 to 6 servings)

The term "curry" is not Indian, but English, and refers to the spice blends used in Indian cooking. The term has been adapted by Singaporeans for some of their own dishes that use Indian-style spice blends. 5 tablespoons vegetable oil 1 large onion, peeled and thinly sliced 2 medium-size cloves garlic, peeled and crushed 1 tablespoon coriander seed 1 teaspoon cumin seeds 1 teaspoon aniseed 2 teaspoons chili powder 1/2 teaspoon crushed red pepper 1 teaspoon tamarind concentrate (available in Oriental groceries), dissolved in 1/4 cup boiling water 1 1/2 cups coconut milk (see recipe below) 1 carrot, sliced into discs 1 medium eggplant (about 1 1/2 pounds), peeled and cut into 1-inch cubes 1/2 pound okra, trimmed and cut in two 2 medium-size tomatoes, chopped 3/4 teaspoon salt 1 teaspoon sugar

In a large saucepan, heat the oil. Saute' the onion and garlic until the onion is soft, about 3 minutes.

To make a rempah paste, grind the spices in a spice grinder or a mortar and pestle. Add the paste to the onions and fry for 2 minutes, stirring constantly. Add the tamarind-water, coconut milk, carrot and eggplant. Bring to the boil, cover, and simmer for 3 minutes. Then add the okra, tomatoes, salt, and sugar. Cook until the vegetables are tender, about 12 to 15 additional minutes, stirring occasionally. Adjust seasonings. COCONUT MILK (Makes 5 1/2 cups)

This recipe will produce more than enough coconut milk to make the chicken kurmah and vegetable curry. Leftover coconut milk may be frozen very successfully for up to three months. The shredded coconut left over from this process has little taste, but adds a nice texture to cookies and cakes. 4 cups shredded unsweetened coconut (available in health food stores) 8 cups boiling water

Using 2 cups of boiling water for each cup of shredded coconut, spin the mixture in four separate batches in a food processor or a blender. Remove to a heatproof pitcher or jar and let stand for 30 to 45 minutes.

Strain the mixture through a fine-meshed strainer, pressing the coconut to release all of the liquid. Refrigerate coconut milk until needed. Discard the shredded coconut or use as suggested above.