Stews of meat and vegetables are universal. Whether they are creamy French blanquettes, Polish sweet-and-sour stews with dried fruit, Boston-style baked-bean casseroles, saffron-spiced Moroccan tajines or Indian and Thai curries, all are based on the same principle.

Chunks of meat are simmered slowly in liquid with seasonings, which gradually penetrate the meat and flavor the sauce. The major role of flavorings is emphasized by the French word for stew, ragout, which is derived from ragouter, meaning to enhance the flavor, a reference to the highly seasoned stews popular in Europe during the Middle Ages.

Old-fashioned meat-and-potato stews are still well-liked, but many of today's stews are even more exciting. A variety of colorful vegetables, and a greater proportion of these than before, add zip to stews and enable them to be satisfying, nutritious and not heavy. Adding a generous quantity of vegetables makes it possible to enjoy the rich taste of meat without consuming a large amount of calories.

One reason for the time-honored importance of stews in home cooking is that they are economical. Low-priced cuts of meat are ideal for stew, not only because they become very tender in the slow cooking, but also because they yield a delicious sauce. Shoulder cuts of lamb, beef and veal are perfect for stews, as are chicken pieces, which have the advantage of giving a flavorful stew in a short time.

In spite of their relatively long simmering times, stews are suited to the busy cook. They do not demand much attention while they cook and they can be made ahead. Most stews are even better when served the next day, because the ingredients have been in contact for a long time. It is often practical to prepare stews in large enough quantities for several meals, and to refrigerate or freeze them for reheating later. Some vegetables, however, are better when slightly crunchy and should be added to the stew just before it is served.

Beef, veal or chicken stock are the best cooking liquids for stews. Water can be used instead, either combined with a little wine or chopped tomatoes, or with a liberal amount of spices and herbs, especially the more assertive ones such as curry, cumin, saffron, basil, cilantro, rosemary, thyme, oregano or mint.

There are several ways to thicken the cooking liquid of stews. Vegetables give body to some stews, as in Basquaise Chicken With Peppers and Tomatoes. Others, such as Beef Stew With Winter Squash, utilize a little flour. Still others, such as Veal Stew With Artichokes and Peas, have a light sauce that does not cling to the meat and are best served in shallow bowls.

The thickness of the cooking liquid can also vary according to the type of casserole used and the strength of the flame, but is easy to adjust. If a stew is too thick, a little more liquid can be added toward the end of the cooking time to bring it to the desired consistency. If it is too thin, the meat and vegetables can be carefully removed with a slotted spoon and the liquid boiled until it becomes thicker and more concentrated.

Because many stews are practically a dinner in one pot, they make menu planning easy for both entertaining and day-to-day cooking. Little is needed to complete the meal. Noodles, rice, potatoes or crusty bread can accompany the stew; a light salad can be served before or after it; and fruit or a simple dessert can follow. Many stew casseroles are attractive enough to bring to the table, thus simplifying serving.

The word stew might evoke images of plain cooking to some, but it is amazing, in today's fast-moving life style, how much they are appreciated, both by those who are nostalgic for their mother's stews and by others whose childhood food memories consist mainly of hamburgers. LAMB STEW WITH MINT AND CELERY (4 servings)

If desired, this stew can be made with beef chuck instead of lamb.

3 tablespoons vegetables oil

2 pounds boneless lean shoulder of lamb, cut into 1 1/4- to 1 1/2-inch pieces, trimmed of fat and patted dry

1 large onion, chopped

1 tablespoon all-purpose flour

2 cups water

1/4 teaspoon firmly packed crushed saffron threads (optional)

Salt and pepper

1 tablespoon tomato paste

1 pound celery (5 large stalks), peeled, halved lengthwise and cut in 2-inch pieces

2 tablespoons minced fresh mint

1 teaspoon fresh strained lemon juice

Heat 2 tablespoons oil in a large heavy enameled cast-iron or stainless steel casserole over medium-high heat. Add half of lamb and brown it, about 7 minutes. Using slotted spatula, transfer it to plate. Repeat with remaining meat.

Add onion to casserole and cook over low heat, stirring often, until softened, about 7 minutes. Return meat to pan, reserving any juices on plate, and sprinkle meat with flour. Toss lightly to coat meat with flour. Cook over low heat, stirring often, 5 minutes.

Stir in water and juices from plate and bring to boil, stirring often. Add saffron, salt and pepper. Cover and cook over low heat, stirring and turning lamb cubes over occasionally, until lamb is very tender, about 1 to 2 hours; when pierced and lifted with thin-bladed sharp knife, it should fall from knife. Stir in tomato paste.

Heat remaining tablespoon oil in large skillet over medium-high heat, add celery and saute' until it begins to soften but not to brown, about 3 minutes. Add celery pieces to stew and push them down into sauce. Simmer until celery is just tender, about 15 minutes.

Sauce should be thick enough to lightly coat spoon; if it is too thin, uncover and simmer over low heat, stirring occasionally very gently, until lightly thickened, about 10 to 15 minutes.

Remove from heat. Stir in mint and lemon juice. Taste and adjust seasoning. Serve stew from enameled casserole or deep serving dish. BEEF STEW WITH WINTER SQUASH (4 servings)

2 tablespoons plus 2 teaspoons vegetable oil

2 pounds boneless beef chuck, cut into 1 1/4- to 1 1/2-inch pieces, trimmed of fat and patted dry

1 large onion, chopped

1 tablespoon plus 1 teaspoon all-purpose flour

1 1/4 cups dry white wine

1 3/4 cups water

1 tablespoon soy sauce

1 cinnamon stick, about 2-inches long

Pinch pepper

1 1/2 pounds winter squash (such as banana squash)

1/3 cup dark raisins

2 tablespoons mild honey

1/3 cup whole blanched almonds

2 teaspoons fresh strained lemon juice

Heat 2 tablespoons oil in a large heavy enameled cast-iron or stainless steel casserole over medium-high heat. Add half of beef and brown it, taking about 7 minutes. Using slotted spataula, transfer it to plate. Repeat with remaining beef.

Add onion to casserole and cook over low heat, stirring often, until softened, about 7 minutes. Return meat to pan, reserving any juices on plate, and sprinkle meat with flour. Toss lightly to coat meat with flour. Cook over low heat, stirring often, about 5 minutes.

Stir in wine, water, juices from plate and soy sauce; add cinnamon stick and pepper and bring to boil, stirring often. Cover and cook over low heat, stirring and turning beef cubes over occasionally, until beef is very tender when pierced with a knife, about 2 hours. Discard cinnamon stick.

Meanwhile, scrape off any stringy parts from center of squash with spoon. Cut squash in large pieces, cut off peel and cut squash in 1-inch cubes. When meat is tender, stir in honey. Add squash and raisins and push squash down into liquid. Cover and simmer 10 minutes. Turn squash pieces over, cover and simmer until squash is tender, about 15 minutes.

Sauce should be thick enough to lightly coat spoon; if it is too thin, uncover and simmer over low heat, stirring occasionally very gently, until lightly thickened, about 10 to 15 minutes.

Heat 2 teaspoons vegetable oil in medium skillet over medium heat. Add almonds and saute', tossing them often with slotted spoon, until lightly browned, about 3 minutes. Transfer to paper towels and sprinkle lightly with salt.

Remove stew from heat and stir in lemon juice. Taste and adjust seasoning. Serve stew from enameled casserole or deep serving dish. Serve almonds separately. BASQUAISE CHICKEN WITH PEPPERS AND TOMATOES (4 servings)

1 fresh jalapeno pepper, cored and seeded

2 large cloves garlic

5 tablespoons vegetable oil

1 large onion, chopped

1 green bell pepper, cored, seeded and chopped

1 1/2 pounds ripe tomatoes, peeled, seeded and chopped

Salt and pepper to taste

3 1/2-pound chicken, cut in 8 pieces, patted dry

Mince hot pepper and garlic in food processor and reserve. Heat 3 tablespoons oil in a large saute' pan or deep frying pan. Add onion and cook over low heat, stirring often, until soft but not brown. Add bell peppers and cook 5 minutes. Add hot pepper and garlic and cook, stirring, for 5 minutes. Add tomatoes and salt and cook uncovered over medium heat, stirring often, 15 to 20 minutes or until mixture is thick. The tomato-pepper mixture can be prepared 2 days ahead and kept in the refrigerator.

Sprinkle chicken with salt and pepper. Heat remaining 2 tablespoons oil in a large saute' pan or deep frying pan. Add half of chicken pieces and saute' over medium-high heat until browned on both sides. Remove to a plate. Saute' remaining pieces. Discard fat from pan.

Return chicken pieces to pan and add any juices that accumulated on plate. Add tomato-pepper mixture. Cover and cook over low heat about 30 minutes or until chicken is tender. Taste for seasoning. If sauce is thin, remove chicken pieces and boil sauce until thickened. Return chicken to sauce for serving. VEAL STEW WITH ARTICHOKES, PEAS AND SAFFRON (4 servings)

2 large pinches of saffron threads (about 1/4 teaspoon)

About 2 1/4 cups veal stock, chicken stock or water

1 tablespoon vegetable oil

3 tablespoons butter

2 pounds boneless veal shoulder or veal stew meat, cut in 1 1/2-inch cubes

3 medium cloves garlic, chopped

1/4 teaspoon salt

1/4 teaspoon pepper

3/4 teaspoon ginger

3 medium artichokes*

1 lemon, halved

1 1/2 pounds fresh peas, shelled (about 1 1/2 cups) and rinsed*

1 to 2 tablespoons chopped fresh basil or parsley

Crush saffron between your fingers. Add to 1/4 cup hot stock or water and leave to soften for 20 minutes.

Heat oil and 1 tablespoon butter in a heavy casserole over medium-high heat. Add enough veal cubes to make one layer and brown them. Remove to a plate with a slotted spoon and repeat with remaining veal cubes.

Reduce heat to low. Add garlic and cook 1/2 minute. Add saffron liquid to casserole and bring to a boil, stirring to dissolve any brown bits in casserole.

Return veal to casserole and add any juices from plate. Sprinkle with salt, pepper, and ginger and stir over low heat to coat meat with spices. Pour in remaining 2 cups liquid. Bring to a boil, skimming off froth that rises to top. Reduce heat to low, cover, and simmer, stirring occasionally, until veal is just tender when pierced with a knife, about 1 1/4 hours.

Meanwhile, prepare artichoke bottoms: Squeeze juice of 1/2 lemon into a bowl of cold water. Break or cut off the stem of an artichoke. Break off largest leaves at bottom. Put artichoke on its side on a cutting board. Holding a very sharp knife or a serrated knife against side of artichoke, cut lower circle of leaves off, up to edge of artichoke bottom. Turn artichoke slightly after each cut. Rub edge of artichoke bottom well with cut lemon. Cut off central core of leaves just above artichoke bottom. Cut off leaves under base and trim base so it is round. Rub again with lemon. Put artichoke in bowl of water. Continue with remaining artichokes. Cut each artichoke in 4 pieces. Using a teaspoon, scoop out the hairlike "choke" from center of each piece. Return to water until ready to cook.

When veal is tender, remove it to a bowl with a slotted spoon. Spoon about 1 cup of cooking liquid into a saucepan. Add artichoke pieces. If necessary, add enough hot water to barely cover them. Cover and cook over low heat for 10 minutes. Uncover and continue to simmer until tender (about 15 minutes).

Pour remaining veal cooking liquid into another saucepan. Add peas and bring to a boil. Reduce heat to medium-low and simmer, uncovered, until just tender (about 10 minutes).

Return veal to casserole. When artichokes are tender, transfer them to casserole, using a slotted spoon. Boil artichoke cooking liquid until reduced to about 1/2 cup and add to casserole. Add peas and their cooking liquid. Simmer uncovered for 5 minutes. Stew can be kept, covered, up to 2 days in refrigerator; reheat in covered casserole over low heat.

Add remaining butter to casserole and heat over low heat, shaking casserole gently, just until butter is absorbed. Add half the basil. Taste, and add salt and pepper if needed.

Serve stew from the casserole or from a deep serving dish. Sprinkle with remanining basil just before serving.

*For a quicker dish, you can substitute 12 frozen artichoke quarters and 1 1/2 cups frozen peas instead of preparing fresh ones. Reduce total artichoke cooking time to 10 minutes and peas to minutes.