This month's Consumer Reports offers impressive testimony that the food processor is no passing fad. The cover story is titled: "CU Rates 15 Food Processors . . . Does Cuisinart Still Beat Its Rivals?"

To relieve suspense, the answer is yes.

Of more significance, however, is the number of processors now on the market. In mid 1977, testers for Consumers Union found only three rivals to pit against Cuisinart. Now there are 14, plus La Machine, a French product that isn't really a food processor. La Machine has been sold as an alternative because it chops and shreds. Citing poor performance and the inconvenience of changing parts and attachments for each function, Consumer Reports downgrades it as "awkward, complex, and medicore."

For those who may not have visited a cookware store or appliance department in the past three years, the food processor is a compact piece of electrically-powered equipment that chops, slices, shreds and blends foods with remarkable speed. Strong blades do the work within a plastic bowl. It is more versatile than the electric blender, stronger than most mixers. (The blender is better with liquids, though, and the mixer will beat egg whites and has greater capacity.)

There is a tendency to call any food processor "Cuisinart," just as the words soft drink and "Coke" often are interchanged. Cuisinart is a brand Manufactured in France, it was the prototype home food processor. (An industrial model, the Robot Coup, began it all.) It is still the performance leader as well as the most expensive in the field. So Cuisinart almost always is used as the standard of comparison.

While there is a consensus among experts that Cuisinart sells the best food processors, only a few of its competitors are clearly inferior. As tests by Consumers Union and others have shown, Cuisinart has a few shortcomings of its own. The others do the same work, perhaps not as well, but probably well enough. The difference in price may not justify the difference in performance, especially if the food processor is not used regularly. In the manner one chooses an automobile, the prospective buyer should consider her or his own desires and needs and weigh them against the price.

Those who bought a processor some time ago may be disappointed to learn how well some of the newer models perform and may be irritated at the current wide spectrum of prices. In addition, with more brands available there has been considerable discounting. Cuisinart, which once had a single model priced at $225, now has two. The metalbase (CFP5A) is $200. The plastic-base (CFP9) is $140. A third Cuisinart model with larger capacity, the Japanese-made DLC-7, is expected to go on sale here next month at about $250.

Another Japanese product, being introduced this week at the Kitchen Bazaar stores, is Mighty Chef II. It has many of the features of the new Cuisinart, but the price tag - $100 - is substantially lower. (In the Consumer Reports' test, the original Mighty Chef did well, but the magazine gave higher ratings to the processors of Sunbeam, Omnichef, J.C. Penney and Sanyo.)

According to Consumer Reports, which is not given to touting expensive gadgets, "a food processor is a very useful kitchen appliance." Nonetheless, most experts agree that it should not be seen as essential. It is merely a preparation tool. While it can save considerable time and effort, using it is not effortless. Food must be pre-cut and fed into the machine in limited amounts if it is to function properly - or in some cases, function at all.

A food processor does seem to raise the consciousness of the would-be gourmet. Doing quenelles, pates, dough for brioche or paste become considerably less formidable challenges. But if you have no interest in making such foods, a food processor may not be the appliance for you. At the other extreme, some cooks, particularly those for whom cooking is a hobby or therapy, prefer to do without the benefits of technology. They like to chop parsley with a knife and do other time-consuming tasks by hand.

In the course of an interview in this month's Bon Appetit magazine, Julia Child put things in perspective. "What do you think about the food processor?" she was asked. "Marvelous, the most important kitchen implement invented since the electric mixer," she answered. But moments before she has been asked "What tools do you consider indispensable in your kitchen?" Her response was "a good knife and a good frying pan."

In addition to weighing the food processor's usefulness, the consumer who has not yet purchased one might well wonder about waiting a litte longer. With so many new brands, and the spate of "improved" models on the market, won't the food processor become even better and perhaps cheaper?

Perhaps, but there is a danger as well. Competition tends to bring "improvements" to appliances that make them more complex (and therefore more liable to breakdown), yet really don't improve the machine at all. General Electric has devised a blender attachment for its food processor. Hamilton Beach has built a "metric/English measurement calculator" into its Model 2002. It offers 16 speeds, a 1- to 60-second timer and a panel with 24 buttons to push. All for $160.

"I don't see many new processors upcoming," said one merchant. "The next step will be new attachments and possibly-more blades."

My own feeling shows the bias of a man who has given up on the blender. An old, two-speed model performed splendidly. When the bowl was broken, I discovered I could not replace it. Home models are equipped with at least eight speeds these days. I don't need eight speeds to accomplish what two did very well, so I refuse to buy one.

"Elaborations, that's what spoiled the blender," said the merchant.

The odds are at least 8 to 2 that something similar will happen to food processors.

In the meantime, here are several recipes that show off the processor's capabilities. Marie-Therese Colonna, the respected Falls Church cooking teacher, does her cucumber hors d'oeurve by hand, but it survives the transition to a processor. The recipe for Lemon-Nut Soufle Cake comes from "Cooking with the Cuisinart" by Roy Andries de Groot McGraw-Hill, $12.95), still the best book in the field for the ambitious cook. The instructions have been adapted and shortened. CREAM OF CARROT SOUP

(8 to 10 servings) 1 pound carrots, peeled and cut in chunks 1/2 onion, coarsely chopped 2 tablespoons butter 1/2 bay leaf 1/2 teaspoon thyme 4 or 5 sprigs parsley 1 quart chicken or beef broth, or a mixture of the two 1 teaspoon dried dill or 1 tablespoon chopped fresh 1/2 pint whipping cream Salt and pepper to taste

Melt butter in a large sauce pan. Add carrots and onion and saute until onion is soft. Add bay leaf, thyme, parsley and broth. Bring to a boil, then lower heat and simmer until carrots are tender.

Using a slotted spoon, transfer carrots, onion and a small amount of broth to the bowl of a food processor equipped with the steel blade (discard bay leaf and parsley. Puree the vegetables then return to the saucepan. Add dill and cream and stir to achieve an even consistency. Reheat to a simmer. Season with salt and pepper as desired and serve hot, or chill and serve cold. HOT POTATO CHOWDER (8 to 10 servings) 1 pound potatoes, peeled and cut into pieces 1/2 onion, coarsely chopped 1/2 tablespoon thyme 1 cup clam juice 3 cups chicken broth 2 cut-up scallions, white and green parts, or 4 or 5 sprigs parsley, stems removed 1 cup light cream or milk Salt to taste Butter Paprika

Place potatoes and chopped onion in a saucepan along with thyme and broth. Bring to a boil and simmer, covered, until potato is tender. Transfer vegetables to the bowl of a food processor equipped with a steel blade along with a small quantity of broth. Add the scallions or parsley and puree. Return to the saucepan and stir in along with the cream. Taste and add salt if desired. Reheat, then pour into soup bowls over a pat of butter. Sprinkle with paprika before serving. EGG PASTA (4 servings) 2 cups flour, semolina or allpurpose 1/2 teaspoon salt 2 extra-large eggs 1 tablespoon olive oil

Place flour and salt in bowl of a food processor equipped with a steel blade. Whirl briefly to sift flour. Add eggs and oil through feed tube and run processor until a ball of dough forms. (Add warm water in small quantities if dough remains grainy.) Cover dough with an inverted bowl and leave for 20 to 30 minutes. Shape and cut with a pasta machine. SPICY PASTA SAUCE (4 servings) 2 slices stale bread, without crusts 1/4 cup chopped parsley 2 cloves garlic 6 to 8 anchovy fillets 1 red chili pepper, chopped, or 1/2 teaspoon hot pepper flakes 1/2 cup olive oil Salt to taste

Prepare breadcrumbs and parsley separately in processor, using metal blade. Set aside. Chop garlic, then anchovies. Set aside until pasta is cooking. Then heat oil in a frying pan. Add garlic and cook until it begins to brown. Add anchovies and stir for 30 seconds. Add breadcrumbs and red pepper and cook for about a minute, stirring. Add parsley. Stir to mix well, then toss with drained pasta and serve at once. MADAME COLONNA'S CUCUMBER HORS D'OEUVRE (Makes about 2 cups) 2 large cucumbers, peeled, cut in half lengthwise and seeded 1 tablespoon finely chopped onion 1 tablespoon finely chopped green olives 1 to 2 teaspoons finely grated lemon rind 1/4 teaspoon curry powder, or a bit more to taste 1/4 teaspoon ginger, or a bit more to taste Salt and pepper to taste 2 ounces cream cheese, softened or cut in pieces Chopped parsley and drained capers for garnish

Slice cucumber with appropriate blade. Toss with 1/2 teaspoon salt and transfer to a plate. Cover with a weight and leave for 30 minutes. Drain and squeeze cucumbers in a towel to remove as possible liquid. Return to processor with steel blade. Chop finely. Add onion, green olives and lemon rind and chop. Add seasonings. Mix. Then add cream cheese and puree until thoroughly mixed.

Place in a bowl and garnish with parsley (prepared in the processor) and capers. Alternatively, the mixture may be transferred to a wet, chilled 2-cup mold and placed in the refrigerator for 2 to 3 hours, then unmolded just before serving with melba toast. If well covered, this will keep in the refrigerator for two or three days. ROY DE GROOT'S LEMON-NUT SOUFFLE CAKE (8 to 10 servings) 1 pound shelled hazelnuts or filberts 2 lemons 2 1/4 cups granulated sugar (about) 10 large egg yolks 2 teaspoon pure vanilla extract 1 tablespoon butter 1/2 cup superfine sugar 12 large egg whites 2 cups heavy cream (optional)

Chop the nuts, in two batches, using the steel blade and stopping and restarting the processor every 3 or 4 seconds until they are finely ground. Reserve each half separately.

Remove the peel from the lemons with a zester or potato peeler and chop in the processor. When finely minced, add 2 cups granulated sugar and blend for 10 to 15 seconds. Reserve in a third bowl.

Place 5 egg yolks in the bowl with the steel blade. Run briefly to break up yolks, then add half the lemon-flavored sugar, half the nuts and 1 teaspoon vanilla extract. Mix thoroughly. Transfer to a mixing bowl.

Repeat this operation with the remaining yolks, sugar, nuts and vanilla.

Preheat oven to 300 degrees.

Select a 10-inch tube pan with a removable bottom. Lightly grease the bottom and sides with butter, then sprinkle on a thin coat of superfine sugar.

Beat the egg whites until they stand up in stiff peaks. Then, with a rubber spatula, gently fold them into the nut mixture. Pour at once into the tube pan and set in the center of the oven. Cook for 2 hours without opening the oven door. Test with a knife point or cake tester (it should come out dry). When done, remove from oven and let cool completely in the pan.

Squeeze juice from the 2 lemons and place in the bowl of the processor with the steel blade. Add 1/2 cup superfine sugar and mix briefly. Spoon over the cake. Let the cake set overnight before cutting and serving. If desired, whip heavy cream just before serving and mound it in the center of the cake.