FOR YEARS, Helen Bagnato has counted on her daughters Jane and Regina to produce the elegant holiday cookies that are the hallmark of the Bagnato family gathering in Fairfax Station, Va. Each Christmas she makes sure her prized English tray is shined and ready to display not only their prized pastries and candies -- but especially their cookies. The tender traditions include the raspberry-laced Linzer Tarts, rich with butter; dark, delicate Mintywiches -- chocolate concoctions that sandwich mints between two cookies hot from the oven; airy Chocolate Shells, cookies shot full with a silky buttercream mixture; light Valencia Shortbread Fingers, oozing a subtle orange filling and dipped in chocolate.

But this year she's got some competition. Her daughters have started a catering business.

"People have been telling us for years," says Jane Bagnato Boling, "that we should start a business featuring our pastries and cookies. We decided this past fall that the time had come."

Boling, a former French teacher, and her sister, Regina Bagnato Cour, began to pull together their best recipes. They named the business "La Petite Madeleine," in remembrance of Marcel Proust's unforgotten pastry..

Surprisingly enough, the sisters cannot recall a single joint cookiemaking experience from their girlhood. Nor do their cookie recipes originate from their Italian family traditions.

"Our mother didn't bake so much, although she's always been a good cook," says Boling. "But she always encouraged us to bake -- especially for the holidays. We always had dessert at each meal, and I was in charge of it." Cour says she didn't bake at all until she left home.

Boling, of course, rejoiced when Cour began to see the light. She always knew, she says, that her sister -- a college art major -- would find particular pleasure in adding artistic touches to the baked confections.

Turning out delicacies by the dozen is not a casual undertaking, they both say.

"We want a finished-looking cookie. It has to be artistic," explains Boling. "We want the cookies -- whether they're for our own family gatherings and friends or for the business -- to be both unforgettable in taste and beautifully presented."

They are. Rather than leave a tender, flaky Viennese Round bare, the sisters drizzle the top in a delicate, pink pinwheel design. Each cake-like Venetian Square -- already festive with three distinct, pastel-colored layers -- is adorned with a fragile flower, blooming from a thin, firm chocolate glaze. In presenting the cookies, the women take care to arrange them not only according to contrast in appearance, but also taste and texture. The syrupy, sweet Pecan Diamonds, for example, line up nicely alongside the less rich, flaky Viennese Fingers.

Practicality is not sacrificed for the sake of art. "Besides looking good and tasting special," says Cour, "all of our cookies have to freeze well -- decorations and all. It just isn't practical any other way."

Since the two usually have baked 70 to 80 dozen cookies each year for family and friends, their make-ahead capabilities promised to be even more essential for this, their first professional holiday season.

In the past each sister set aside a week in early December for nothing but baking -- each one averaging production of two or three similar kinds of cookies each day. By concentrating on making similar types each day, such as rolled or shaped versus cake-like types, the women find increased efficiency in production. "We've found that doing it this way makes for far less waste of time," says Boling. "Clean-up is easier, too."

Rarely do the two bake together. They operate with a definite division of labor, based on which types of cookies each excels at making: "Regina hates to roll, so I make the shaped cookies, like the Linzer Tarts," says Boling. Cour, on the other hand, makes the Mintywiches. "You have to work fast," she says. "Jane just doesn't enjoy making them as much as I do."

The cookies they have found to be most popular with crowds are, invariably, "anything with chocolate." Mintywiches generally rate tops on the list of chocolate favorites, with Chocolate Shell cookies close seconds.

While the sisters insist that making such elegant cookies should not intimidate inexperienced bakers, they admit that some cookies -- such as their airy Cherry Horns, made of delicate dough that is shaped around hot iron horns -- are certainly not good choices for the beginner.

"By the time we got the hang of making those Cherry Horns the first time, I think we could have charged $5 a cookie and still not have gotten them to be cost effective," says Boling.

Although each woman is accustomed to turning out dozens of cookies -- alone -- in an afternoon, they say even the most complicated cookiemaking efforts lend themselves well to group undertakings. In fact, with the increased demands placed on them this year, the sisters enlisted family help in October for the holiday season ahead. Boling's husband chops, prepares chocolate shavings, cleans up and generally helps out. The children "like to do everything."

Boling and Cour say the key to producing out-of-the-ordinary cookies in quantity is not only precise planning, but teamwork in the kitchen. A few other tips:

* To insure that cookies are the same size, measure dough precisely. Always use measuring spoons, not kitchen spoons.

* When cutting bar cookies, such as Venetian Squares, use a ruler to measure individual pieces after marking lightly before cutting.

* Using a long serrated knife, cut bar cookies in one single downward motion without pulling the knife through the cookie.

* Be simple but original in decorating cookies. Use tinted coconut, candied cherries or other fruit, toasted almonds, buttercream rosettes or simple drop flowers.

* Flash-freeze cookies by placing in the freezer, uncovered, on cookie sheets. When they are frozen, place cookies in appropriate containers. Thaw cookies, uncovered, at room temperature -- removing from the freezer only what you need.

* For a finished look, place small cookies or cakes in candy or petits fours papers. Arrange the cookies on a tray or plate in pleasing contrasts of color, taste, and texture. PECAN DIAMONDS (Makes 1 1/2 dozen) For the cookie: 1 cup all-purpose flour 1/2 cup firmly packed brown sugar 1/2 cup butter Filling: 1/4 cup all-purpose flour 1/2 cup firmly packed brown sugar 2 eggs, slightly beaten 1/2 cup dark corn syrup 1 teaspoon vanilla 1/4 teaspoon salt 1 1/4 cups chopped pecans

For cookie base, mix one cup flour and brown sugar together. Cut in butter until fine crumbs form. Pat into greased 8-inch square pan. Bake at 350 degrees for 20 minutes. Remove from oven.

Mix filling ingredients together. Pour over crust, then bake 30 minutes or until top is set. Cool.

Carefully loosen and turn out of pan onto cutting board. Trim edges. To cut diamonds, first cut lengthwise into 1 1/4-inch strips. Then cut diagonally to form diamonds. VALENICA SHORTBREAD COOKIES (Makes 30 cookies) 1 cup butter, softened 1/2 cup sifted confectioners' sugar 1/2 teaspoon vanilla 2 cups all-purpose flour 1/4 teaspoon baking powder Orange buttercream filling: 4 tablespoons butter, softened 1 cup sifted confectioners' sugar 3 teaspoons orange juice concentrate 1/2 teaspoon grated orange peel Frosting: 2 1-ounce squares semi-sweet chocolate 2 teaspoons shortening Chocolate shot (sprinkles)

Cream butter, confectioners' sugar and vanilla until light and fluffy. Stir together flour and baking powder. Mix dry mixture into butter mixture. Using medium star design of cookie press, press out strips 3 inches long onto ungreased cookie sheet, placing about one inch apart. (If dough does not come through cookie press smoothly, add 1 to 2 teaspoons cream.) Bake at 375 degrees about 7 minutes, or until very lightly browned around the edges. Cool.

Beat filling ingredients together in small mixing bowl until smooth. Frost bottom of one cookie with orange buttercream and sandwich together with other cookie. Repeat for all cookies.

To make the frosting, melt chocolate squares with the shortening in the top of a double boiler over hot water. Dip one end of cookie sandwich in chocolate, then roll in chocolate sprinkles. MINTYWICHES (Makes 10 dozen) 2/3 cup butter, softened 1/2 cup granulated sugar 1 egg 6-ounce package chocolate chips, melted 1/4 cup light corn syrup 1 3/4 cups flour 2 teaspoons baking soda 1/4 teaspoon salt Granulated sugar 50 to 60 Andes Creme de Menthe mint wafers, halved

Combine butter, sugar and egg in large mixing bowl and beat until light and creamy. Blend in melted chocolate and syrup. Sift together flour, soda and salt. Stir into chocolate mixture. Chill several hours or overnight.

Using a rounded 1/4 teaspoon of dough, shape into a ball and roll in granulated sugar. Repeat for all dough and place cookies on ungreased cookie sheets. Bake at 350 degrees for 10 to 12 minutes. Remove each batch from oven and let stand just a few seconds. Do not cool. Turn half of each batch upside down and top each cookie with a mint half. Top them with second cookie. Place Mintywiches in the freezer on flat trays or cookie sheets to harden.

Hint: This dough becomes sticky and hard to manage at room temperature. Return it to the refrigerator between batches. VENETIAN SQUARES (Makes 6 dozen) 8-ounce can almond paste 1 1/2 cups butter, softened 1 cup sugar 4 eggs, separated 2 cups sifted flour 1/4 teaspoon salt 10 drops green food coloring 8 drops red food coloring 12-ounce jar apricot preserves 3 squares semi-sweet chocolate

Break up almond paste with a fork, working out any lumps. Add butter, sugar and egg yolks, beating until light and fluffy (about 5 minutes). Beat in flour and salt.

In small bowl, beat egg whites until stiff peaks form. With wooden spoon, fold egg whites into almond mixture.

Grease 3 13-by-9-by-2-inch pans. Line each with waxed paper and grease again. Remove 1 1/2 cups of the batter and spread into one of the prepared pans. Remove 1 1/2 cups more of batter and add green food coloring. Spread this into second pan. Add red food coloring to remaining batter and spread into last pan. Bake each pan at 350 degrees for 15 minutes or just until edges are golden. Cakes will be 1/4-inch thick.

Remove cakes from pans immediately onto large wire racks. Peel off waxed paper and cool thoroughly. Place green layer on jelly roll pan. Heat apricot preserves and strain. Spread half the strained preserves on the green layer and top with yellow layer. Spread remaining preserves on yellow layer and top with pink layer. Cover with plastic wrap and weight down (a large dictionary works well) in refrigerator overnight.

Melt chocolate in top of double boiler over hot, not boiling, water. Spread over pink layer. Let dry 10 minutes. Trim edges off cake. Cut into 1-inch-square pieces.