THE FRUIT of the 25 tomato plants in Santina Bayerle's Chevy Chase back yard won't be ready for eating until Christmas.

It's not that her plants are late bloomers by any means. The tomatoes will ripen over the next two weeks, just like everybody else's. The difference is that her bright red tomatoes will get a cold water bath, be split down the middle, and go back in the sun for another week or so for a good solar drying. When they're almost "paper-dry" she will pack the tomato halves in jars and marinate them in garlic, olive oil, oregano and salt and pepper for three to four months.

You can't use just any tomato for sun-dried tomatoes, says Bayerle, describing the recipe she learned by watching her grandmother make them 30 years ago in Bari, Italy. "YouIn the Garden have to pick the best. They must be fleshy Italian plum tomatoes, and they must be blemish-free."

"Americans have had a love affair with the tomato for years," says Giorgio DeLuca, co-owner of Dean and DeLuca, a food specialty shop in New York City. "Well, sun-dried tomatoes are just another version. They have an aggressive flavor that lingers and lingers." DeLuca says he sells 250 pounds of imported Italian dried tomatoes to shoppers each week, at $18 a pound. "I sell all I can get." While they are the current rage, DeLuca says, sun-dried tomatoes weren't selling in the United States 30 years ago. "Importers couldn't get them beyond being ethnic food."

DeLuca wholesales his sun-dried tomatoes to outlets in Washington, among them Suzanne's on Connecticut Ave. and Sutton Place Gourmet on New Mexico Ave. They retail here for less than they do in New York--$14.95 a pound at Suzanne's and $13.96 a pound at Sutton Place Gourmet.

"I laugh when I think about all the publicity they're getting recently," says Suzanne Reifers. "I've been selling them in my shop since it opened two and one-half years ago. Just recently people are coming in and saying, 'What's all this I hear about sun-dried tomatoes?' "

Unfortunately the prices keep going up.Two years ago they were $9.95 a pound in her shop, Reifers says. Presently she sells about three pounds of sun-dried tomatoes a week. Jeff Cohen, owner of Sutton Place Gourmet, says he sells 25 pounds a week. That's a lot of tomatoes, considering that you get about 50 whole sun-dried tomatoes to a pound.

If this seems a little pricey, a minor week-long commitment can get you your own, says Bayerle. Select perfect tomatoes: fleshy, plump, bright red and blemish-free. After washing in cold water, split them down the center (from top to bottom), leaving in the pulp. While they usually get an initial sprinkling of salt--"that's the rule," says Bayerle--she's found that's not absolutely necessary. Lay the tomatoes on paper towels in the yard away from gardens and other bug-infested areas. Bugs, Bayerle says, are "one of the reasons sun-dried tomatoes are difficult to make." Yards with dense bug populations may be unsuitable. She sprays the grass with insecticide and sets the tomatoes up high. Bring them in at night and keep them out of the rain or they will be ruined. They need constant sunlight, she says. "I remember it was a game as a child. Every time the sun would move two inches, we'd run out and move the tomatoes." Watch them constantly, as mildew can form just under the edge of the slices where they curl, she warns. "When they mildew I throw them away."

After they've sunbathed for a week, put a layer of tomatoes in the bottom of a wide-mouth screw-top jar and sprinkle with salt, pepper, minced garlic and oregano. Continue packing until the jar is filled, alternating layers of tomatoes and spices. Submerge the contents of the jar in good Italian olive oil, cap tightly, and leave them to sit until Christmas. "My son-in-law loves them and my husband simply adores them," Bayerle says. She's excited over this year's crop of tomatoes because it is so hearty.

Nicole Genovesi, a Dayton, Ohio, entrepreneur, has been drying tomatoes for over 20 years. She learned the basic technique while visiting her husband's relatives in Sicily, but she's changed to using a dehydrator in order to overcome the East Coast humidity and the problems of mildew. This year she'll bottle 150 cases in safflower oil, garlic and oregano to sell under her own label by mail in early October. "In Italy they have two to three months without rain, and do it on rooftops during the season," she explains. But on the East Coast you never can predict the weather so she sets her tomatoes in a dehydrator for 30 hours.

Whether you buy them or bottle your own, sun-dried tomatoes are colorful, spicy additions to many dishes. Of course you have to love the taste of tomatoes, because, "once you dry anything, you concentrate the flavors," Cohen says.

For your first bite of sun-dried tomatoes, get some crusty Italian bread, a little prosciutto, goat cheese and a full-bodied red wine, and treat yourself to a picnic. Once you're in love with them, add the tomatoes to your favorite dishes or use them as a colorful garnish with fresh parsley. Julienne and stuff them into trout and top with parsley sauce for a light summer meal. They're also beautiful in Carol Mason's West Coast pasta salad. After you've used up most of the tomatoes, use the remaining oil on Nicole Genovasi's bread, flecked with the last tomatoes in the jar. SUZANNE'S TOMATO-STUFFED RAINBOW TROUT WITH PARSLEY SAUCE (4 servings) 4 boned trout, about 1 pound each 4 leeks 1 cup vermouth plus 3 tablespoons for the pan 2 cloves garlic 2 shallots 5 tablespoons butter 16 sun-dried tomato halves Salt and pepper to taste 2 tablespoons fresh basil, minced Parsley sauce: 2 cups fish stock 5 tablespoons flour 4 tablespoons butter 1 3/4 cups hot milk Salt and pepper to taste 1/2 cup parsley 1/4 cup fresh chervil or 1 tablespoon dried

Wash and dry trout, set aside. Wash and thinly julienne the white parts of the leeks. Put 1 cup vermouth and leeks in a small saucepan and cook slowly until leeks are tender and vermouth is almost evaporated (drain if necessary). Chop garlic and shallots. Heat 3 tablespoons butter, add garlic, shallots and leeks and cook until leeks take on a golden edge. Thinly slice the sun-dried tomatoes. Add the tomatoes, basil, salt and pepper to taste to the leeks. Fill cavity of trout with mixture. Pour three tablespoons of vermouth in a shallow pan. Place trout in pan and dot with remaining butter. Bake at 350 degrees for 10 to 12 minutes.

To make the parsley sauce, reduce fish stock to 1/4 cup. Melt the butter and add the flour, stirring over moderate heat until they foam together without browning for 2 minutes. Remove from heat and when the bubbling stops, quickly whisk in all the hot milk, beating until mixture is smooth. Return to medium-high heat, whisking until sauce thickens and comes to a boil. Stir and boil for 2 minutes and season lightly with salt and pepper to taste. Finely chop the parsley and chervil. Add fumet, parsley and chervil to the sauce. Season to taste with salt and pepper. CAROL MASON'S PASTA SALAD (4 servings) 1 cup cooked spinach shells or other bite-size pasta* 1 cup cooked tomato shells or other bite-size pasta* 1 1/2 cups vinaigrette (recipe follows) 2 cups zucchini, cubed and blanched 1 cup sun-dried tomatoes, sliced 8 ounces feta or chevre cheese, cubed Salt and pepper Fresh spinach for garnish 2 tablespoons each fresh parsley and coriander, chopped

Toss cooked pasta with about 1 cup of the vinaigrette and allow to rest for 30 minutes. (The vinaigrette needs to be absorbed by the pasta.) Just before serving, add the zucchini (cooled), tomatoes and cheese. Add remaining vinaigrette and toss again. Taste and correct seasoning with salt and pepper if necessary. Serve on a bed of fresh spinach and garnish with the chopped coriander and parsley.

*Available at specialty shops or Italian groceries. VINAIGRETTE 1/3 cup vinegar 1 teaspoon salt Pepper to taste 1 teaspoon mustard 1 teaspoon garlic, crushed 1 tablespoon worcestershire sauce 1 cup vegetable oil

Combine all ingredients in a jar with a tight-fitting lid. Shake vigorously until the mustard is incorporated. Taste and correct seasoning if necessary. NICOLE GENOVESI'S ITALIAN BREAD (Makes 4 loaves) 3 envelopes dried yeast 1 cup lukewarm water 1/2 cup oil from the dried tomato jar 2 tablespoons honey 2 tablespoons salt 4 cups lukewarm water or milk, room temperature 12 cups or more unbleached flour 1/2 cup wheat germ 3/4 cup chopped sun-dried tomatoes

Dissolve yeast in 1 cup water. Put the oil, honey and salt in bowl. Add 4 cups water or milk. Add yeast mixture. Add 2 to 3 cups flour and all of the wheat germ, beating 25 strokes. Add remainder of flour 2 to 3 cups at a time, beating after each addition. When dough is too stiff to beat, begin kneading. Add tomatoes and knead l0 minutes by hand. Cover and let rise in warm place until doubled in bulk (about l 1/2 hours). Knead dough again, punch down and shape into 4 loaves. Place in greased 9-by-5-inch loaf pans and let rise again 30 to 40 minutes. Brush with oil. Bake at 350 degrees for about 45 minutes. With cheese and wine, this bread's all you need for a tasty lunch or supper.