No spy has reaped a more satisfying reward than I, and the secret intelligence mission was really quite simple to execute.

It all started some time ago, when I was visiting the Indian capital of New Delhi. A taxi driver, asked what he knew of small inexpensive local restaurants, told me that if I never had eaten the buttered chicken at the Pindi, I hadn't started to live. He convinced me so completely that I simply dumped my bags at my hotel and let him drive me right on to dinner.

We zigzagged the narrow back streets of a clearly middle-class residential neighborhood, where he deposited me in a small square of somewhat seedy little shops and bistros called the Pandara market. One of them was the Pindi, whose chef-owner, Kasturi Lal, stood outside his front door welcoming customers. We noticed at once that the people he welcomed most warmly--obviously the regulars--were all so rotund they might have been blown up with an air pump.

Inside, the Pindi has the complete absence of frills, the efficient simplicity of an American hamburger joint. It had a few other meat dishes on its slightly butter-stained menu, but nobody even asked for it. No doubt about it: this was a one-dish place.

They set before me the big bowl of chicken pieces--each with the texture of satin and velvet--almost submerged in the thick sauce of butter, cream and tomatoes, with a veritable rainbow of subtle spices. My most critical senses were silenced. This is no food for delicate tasting of little bites--for pecking at with pursed lips. You can eat it with a fork and spoon, but this is rather like trying to swim the English Channel in a suit of armor. Most Indians dig in with wedges of their flat breads.

Lal was very willing to sit down and talk, but it very soon became clear that he was not going to give away the secrets of his recipe. He told me that he has been perfecting it for 20 years. It was, originally, a leftover dish--a way of reheating yesterday's chicken that had been baked in a tandoor clay oven. So good was the rehash that very soon the tail was wagging the dog, and today thousands of chickens are "tandoori baked," just so they can make buttered chicken the next day.

I asked Lal about the spices; the dish is never very strongly peppery. It is not a curry.

I returned home without the recipe, filed my notes and forgot about them. Then, came a report from a colleague who had been back to the Pindi, and it was better than ever. Now, apparently, it has been discovered by the diplomatic community of New Delhi, and there often are two or three ambassadorial Rolls-Royces parked outside, while the chauffeurs go in to pick up several "takeout buckets" of buttered chicken for high diplomats and their families. But Lal is as secretive as ever about his recipe. He talks volubly about many steps in the preparation, but there always seems to be a missing link between one operation and another.

It was time to devise a plan. I wrote to about a dozen of my best New Delhi friends, including Americans, Europeans and Indians. I set down all the questions that needed answers from Lal, then divided these questions among my friends. I was sure that if they all asked the same questions, Lal would become suspicious. I suggested that each of the friends go, on a different date, to dine at the Pindi, to order the buttered chicken, then to engage Lal in quite offhand conversation and ask him these specific questions. They should report the answers to me at once, and I would piece them together. I am proud to report that my private intelligence agency has achieved complete success.

My version does not require a tandoor clay oven, and all the Indian spices are easily available in any Eastern specialty food shop. You have to start the preparation the day before because, on the first day, you have to marinate the chicken and barbecue it in a very hot oven (equivalent of tandoori baking), then hold it overnight to develop its flavor and texture. The following day, you slowly simmer the pieces in their glorious sauce. LAL'S INDIAN BUTTER CHICKEN (4 to 6 servings) 3 tablespoons whole cumin seeds 3 1/2- to 4-pound roasting chicken, or capon, halved lengthwise from center of breast down to center of back, skinned 1/2 cup fresh lemon juice For the marinade: 6 cloves garlic, peeled, coarsely sliced 1 tablespoon finely chopped fresh ginger root 6 cardamom pods 1/2 teaspoon hot, red, dried chili flakes 1 tablespoon medium-hot Hungarian paprika Up to 1/2 cup plain yogurt For roasting: 8 tablespoons softened butter For the butter-cream sauce: 3 1/2 cups tomatoes, peeled, chunked, fresh or Italian canned 6 cloves garlic, peeled, coarsely chopped 2 tablespoons finely chopped fresh ginger root 2 1/4 sticks butter About 2 cups whipping cream 2 to 4 teaspoons coarse salt Freshly ground black pepper 4 to 6 chilies, hot, green serrano, fresh or canned, seeded, minced, usually available at Indian, Mexican or Spanish specialty shops 6 cardamom seeds 1 teaspoon caraway seeds 1/2 teaspoon each: ground cinnamon and cloves 1 teaspoon each: coriander seeds, turmeric 1 tablespoon medium-hot Hungarian paprika 1 cup whole shelled pecans 1/3 cup fresh coriander leaves, chopped

Put cumin seeds in frying pan. Heat moderately, shaking 1 to 2 minutes, until seeds give off an aromatic fragrance, begin to crackle slightly and begin to brown. Remove pan from heat; put seeds on sheet of paper to cool. Grind coarsely in spice mill; reserve, covered. (You will need the seeds for the marinade, roasting and sauce.)

Cut chicken in half lengthwise. Cut off its neck and wing tips. Pierce its flesh all over with fork. Using small, sharp knife, make small cuts all over the meat, each about 1/2-inch deep and all of them at intervals of about 1 inch. Put chicken halves into large bowl; paint thoroughly with lemon juice. Make sure that plenty of it goes into the cuts, using your fingertips to massage the liquid into the flesh, continuing for at least 2 or 3 minutes. Pour any remaining juice over chicken--swish the halves around to make sure they are thoroughly wet. Marinate, covered, 1 hour at room temperature.

Meanwhile, prepare the marinade. Put the garlic, ginger root, 2 teaspoons of reserved ground cumin seeds, the cardamom pods, the red chili flakes and the paprika into food processor container with steel blade. With machine running, add 1/3 cup yogurt, tablespoon by tablespoon, until you have a sauce with about the thickness of whipping cream. Do not necessarily use all the yogurt--or, if needed, use a dash more. The job usually will be done in about 10 seconds.

After the first hour, add marinade to chicken; toss to coat and mix. Again, thoroughly wet and massage the flesh. When both halves are well soaked by the sauce, re-cover the bowl. Let stand at room temperature 4 hours.

Have ready a roasting pan with a flat wire grid to raise the chicken halves about an inch or so above the bottom of the pan. Remove chicken from marinade but do not dry; reserve marinade. Rub chicken all over with some of the roasted cumin and plenty of softened butter. Put, cut side down, on grid in pan. Put into center of 550-degree oven. Your objective now is to roast it only partially--usually in about 15 to 20 minutes--because the cooking will be completed tomorrow in the sauce. With this Indian technique of marination, no oven basting is required. The chicken does not dry out.

Let cool; wrap tightly in foil; refrigerate overnight. This sealing and cooling is an essential part of the preparation for final phase tomorrow. Mix pan juices with reserved marinade. Refrigerate overnight in covered jar.

To make butter-cream sauce:

About 1 hour before cooking, remove chicken from refrigerator. Cut into serving pieces (drumsticks, thighs, upper wing sections, breasts cut into portions, fleshy sections of carcass, etc.). Do not bone them. Remove yogurt mixture from refrigerator. Let stand to room temperature.

Put tomatoes, garlic and ginger root in food processor fitted with steel blade. Pure'e until absolutely smooth--usually in 15 to 20 seconds. Reserve.

Heat 8 tablespoons of the butter in large, deep, thick-bottomed saute' pan. When butter is moderately hot, add chicken pieces; turn to coat. Cook, turning chicken, 3 to 4 minutes, until they show the first signs of being very lightly golden. Remove from pan with slotted spoon.

Add reserved tomato mixture to pan. Simmer gently 7 to 10 minutes, until water has evaporated and mixture thickens. Keep stirring and scraping the bottom to encourage the formation and release of the steam.

When the tomatoes have formed what a French chef would call a coulis, a thickish pure'e, but still with enough liquidity to be a sauce, add the chicken pieces with their juice. Reduce heat to gentle simmer; simmer slowly, stirring gently, until chicken is quite soft and the delicate ginger-tomato flavor has invaded the flesh. This usually takes about 15 minutes from the moment when bubbles reappear after the chicken went in. During this time, drop in 6 more tablespoons of butter in little bits neatly spread across the surface, then stir it in. Also dribble in, all over the surface, about 1 1/2 cups of the cream and stir it in. Stir in the reserved yogurt mixture, 1/4 cup at a time, tasting as you add it to achieve a slightly lemon taste. You do not necessarily need to use all of it.

At the end of the first 15 minutes, start very gently working in the spices--and now you should taste as you go. You should add somewhere from 2 to 4 teaspoons of salt. This should not be a very peppery dish, but it can have some bite to it, with up to about 4 minced serrano chilies, plus a few grinds of black pepper, also some spices you will have freshly pre-ground: the 6 cardamom pods, caraway, cinnamon, ground cloves and coriander. Finally, the ground turmeric and the paprika, for color. Stir all these in, extremely gently, remembering that the chicken is now so soft that it will easily break up. When you stir, go around the pan only once--or twice at most.

After about 20 minutes of simmering, work in 4 more tablespoons of the butter and, if you think the sauce needs it, a few more dashes of cream. Also add the cup of pecans and the remaining ground roasted cumin. Take the pan off heat, partially cover it; let it stand 30 minutes.

Just before serving, gently reheat the pan, adjust seasoning as needed. At the very last moment before serving, fold in 1/3 cup of chopped coriander leaves. Serve on very hot plates, taking care not to break the chicken, covering it with plenty of sauce.